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Demystifying Functional Parameters for Irreversible Enzyme Inhibitors

2024; American Chemical Society; Volume: 67; Issue: 17 Linguagem: Inglês

10.1021/acs.jmedchem.4c01721

1520-4804

David E. Heppner, Blessing C. Ogboo, Daniel A. Urul, Earl W. May, Erik Schaefer, Andrew S. Murkin, Matthias Gehringer,

Computational Drug Discovery Methods

InfoMetricsFiguresRef. Journal of Medicinal ChemistryASAPArticle This publication is free to access through this site. Learn More CiteCitationCitation and abstractCitation and referencesMore citation options ShareShare onFacebookX (Twitter)WeChatLinkedInRedditEmailJump toExpandCollapse EditorialAugust 8, 2024Demystifying Functional Parameters for Irreversible Enzyme InhibitorsClick to copy article linkArticle link copied!David E. Heppner*David E. HeppnerDepartment of Chemistry, The State University of New York at Buffalo. Buffalo, New York 14221, United States*[email protected]More by David E. Heppnerhttps://orcid.org/0000-0002-0722-5160Blessing C. OgbooBlessing C. OgbooDepartment of Chemistry, The State University of New York at Buffalo. Buffalo, New York 14221, United StatesMore by Blessing C. OgbooDaniel A. UrulDaniel A. UrulAssayQuant Technologies Inc., Marlboro, Massachusetts 01752, United StatesMore by Daniel A. Urulhttps://orcid.org/0000-0003-2932-0369Earl W. MayEarl W. MayAssayQuant Technologies Inc., Marlboro, Massachusetts 01752, United StatesMore by Earl W. MayErik M. SchaeferErik M. SchaeferAssayQuant Technologies Inc., Marlboro, Massachusetts 01752, United StatesMore by Erik M. SchaeferAndrew S. MurkinAndrew S. MurkinDepartment of Chemistry, The State University of New York at Buffalo. Buffalo, New York 14221, United StatesMore by Andrew S. Murkinhttps://orcid.org/0000-0002-2559-4605Matthias GehringerMatthias GehringerDivision of Medicinal Chemistry, Institute of Biomedical Engineering, University Hospital Tübingen and Institute of Pharmaceutical Sciences, University of Tübingen. 72076 Tübingen, GermanyMore by Matthias Gehringerhttps://orcid.org/0000-0003-0163-3419Open PDFJournal of Medicinal ChemistryCite this: J. Med. Chem. 2024, XXXX, XXX, XXX-XXXClick to copy citationCitation copied!https://pubs.acs.org/doi/10.1021/acs.jmedchem.4c01721https://doi.org/10.1021/acs.jmedchem.4c01721Published August 8, 2024 Publication History Received 24 July 2024Published online 8 August 2024editorialCopyright © Published 2024 by American Chemical Society. This publication is available under these Terms of Use. Request reuse permissionsThis publication is licensed for personal use by The American Chemical Society. ACS PublicationsCopyright © Published 2024 by American Chemical SocietySubjectswhat are subjectsArticle subjects are automatically applied from the ACS Subject Taxonomy and describe the scientific concepts and themes of the article.Equilibrium constantGeneticsInhibitorsKinetic parametersPeptides and proteinsNote Added After ASAP PublicationClick to copy section linkSection link copied!After this paper was published ASAP August 8, 2024, Figure 1 was corrected. The revised version was reposted August 16, 2024.Molecules that possess the ability to form irreversible covalent bonds with their targets are well established in drug development with various examples clinically approved, (1,2) and are featured as the theme of an ACS cross-journal virtual special issue. (3) The formation of a permanently bound complex results in strong pharmacological responses that arise from a prolonged residence time. (4−6) Another appealing attribute of covalent drugs comes from the ability to transform a weak but highly selective compound that would be ineffective as a reversible drug into a highly efficacious and selective agent (e.g., WZ4002 against mutant EGFR). (7) These avenues, among others, have led to a surge of activity to evaluate and discover diverse covalent reactive groups or "warheads" that react with amino acid side chains (e.g., Cys, Lys, etc.) enabling the design of tailored covalent drugs. (8−10) Additionally, variations made to the compound structures to improve noncovalent interactions enable optimization of potency, selectivity, and other properties. (11,12) Collectively, the capacity for medicinal chemists to carry out adequate and efficient evaluation of irreversible inhibitors is critical to affording the desired target profile parameters.Unlike more conventional noncovalent compounds (denoted "reversible" here─reversible covalent compounds are not covered in this editorial), where determination of IC50 or Ki values is commonplace, irreversible agents are more difficult to properly compare in head-to-head assays. (12,13) The main distinguishing attribute of irreversible inhibitors is the time-dependent formation of the covalent bond that can vary significantly between compounds. Therefore, detailed kinetics measurements are required to properly gauge the differences in activity and selectivity of covalent inhibitors. (12,14−16) In this respect, medicinal chemists conduct structure–kinetic relationships (SKRs) for covalent inhibitors, which are akin to the typical structure–activity relationships (SARs). (13) However, due to the elevated complexities and time-demanding nature in characterizing irreversible inhibitors, these assay platforms are not established in many laboratories, and too often the results from these measurements are inappropriately represented.Our research groups are active in studies and the discovery of irreversible inhibitors that require a detailed understanding of their time-dependent inhibition. (9,11,12,17−22) Many groups in industry and academic laboratories have reported diverse irreversible inhibitor functional parameters, which has been an important development within the field. However, the description of certain parameters and their presentation in the literature is far too commonly made in error, and the confusions that arise because of these inconsistencies should be addressed. (12) Admittedly, some of this confusion likely arises from the similarity in the terms used to characterize reversible and irreversible inhibitors. The overall purpose of this editorial is to provide a resource for both new and established investigators to appreciate and consistently reference the various covalent inhibitor functional parameters that are essential for interpreting irreversible drug activity.A summary of mechanisms and functional terms is supplied in Figure 1 as a visual reference for understanding the various terms and expressions seen in the characterization of reversible (noncovalent) and irreversible enzyme inhibitors. Key details and learning points are described hereafter:Figure 1Figure 1. A one-slide summary of the mechanisms of reversible (1-step, noncovalent) and irreversible (2-step, covalent) enzyme inhibitors and accompanying functional parameters.High Resolution ImageDownload MS PowerPoint SlideNoncovalent Reversible Enzyme Inhibitors:A reversible inhibitor (I) binds the free enzyme (E) to form the enzyme–inhibitor binary complex (E·I). The reversible inhibitor binds in an equilibrium process governed by the association (kon) and dissociation (koff) rate constants. (Note that these rate constants are often indicated by various alphanumeric subscripts.)The binding strength of a reversible inhibitor is commonly quantified by its inhibition constant (Ki), obtained from enzyme activity measurements. This constant is equivalent to the dissociation constant (Kd), which is usually measured through binding experiments. Ki is defined according to the law of mass action as the ratio of the product of the concentrations of free E and I divided by the concentration of E·I. Alternatively, Ki can be expressed as koff divided by kon. The use of the lowercase "i" in the subscript differentiates this parameter from the inactivation constant (KI) for irreversible inhibitors (see below), which is denoted with an uppercase "I".The uppercase "K" denotes an equilibrium constant while lowercase "k" indicates a rate constant, and their italicization implies that these values are unknown variables that are changeable (upper right inset in Figure 1).Drug-target residence time (τ), defined as the reciprocal of koff, is the average time the inhibitor remains bound to the enzyme. (4−6) Residence time is a useful predictor of the strength of the pharmacological or biological response of a given inhibitor. (4−6,23) While residence time defines the time a molecule remains bound to the target on average, an often more informative and related metric is the dissociative half-life (t1/2diss = 0.693/koff) that indicates the length of time required for half of the E·I complex to dissociate to free E and I.It is commonly more convenient to determine the half maximal inhibitory concentration (IC50), instead of Ki; however, IC50 values suffer limitations such as the tight binding limit and other factors that lead to variabilities. (24) The Cheng–Prusoff formalism accounts for the variability of IC50 values with respect to the degree of saturation of the enzyme by the competing substrate, which is governed by the ratio of the substrate (S) concentration to its Michaelis constant (KM). (25) Moreover, caution should be taken when converting IC50 to Ki values by this equation, the discussion of which goes beyond the scope of this editorial. (13,25,26)Irreversible (Covalent) Enzyme Inhibitors: Irreversible enzyme inhibitors typically operate through a two-step mechanism that involves initial reversible binding of the inhibitor to form E·I, governed by kon and koff, followed by the formation of the covalent complex (E−I), described by the first-order rate constant kinact.kinact describes the "intramolecular" chemical reaction of E·I to form E−I, and under saturating inhibitor concentrations it is the maximal observed rate of inactivation.The inactivation constant (KI) is defined as the concentration of inhibitor that yields an observed rate constant of inactivation of 1/2kinact.Differences in the reversible binding of the initial noncovalent step (i.e., the first in the 2-step mechanism) of the irreversible inhibitor can be qualitatively assessed through comparison of KI values, although one should apply caution as this term contains kinact.KI and Ki are not interchangeable in much the same way that KM and Kd for the substrate are not interchangeable. The main distinction between KI and Ki is that the former includes the contribution of kinact. (13) Strictly, KI can approximate Ki only when koff is much larger than kinact, which is often the case.Overall covalent inhibitor potency is captured by the second-order inactivation efficiency rate constant (kinact/KI) that is expressed in units of M–1 s–1. kinact/KI is the essential measurement used in medicinal chemistry when assembling SKRs.The kinetic parameters governing irreversible inhibitors are mathematically analogous to those in Michaelis–Menten enzyme kinetics. Specifically, kinact, KI, and kinact/KI obtained by fitting of inhibitory rate constants versus [I] are mathematically analogous to kcat, KM, and kcat/KM, respectively.Various protocols have been established for determining kinact, KI, and kinact/KI values. (12,14−16) Practically, the majority of these protocols obtain "apparent" values, which are subject to variabilities caused by substrate concentrations and KM values, and can be readily converted into "true" values to afford more direct comparison of irreversible inhibitor values. (12,14,27)Recent reports have presented irreversible covalent inhibitor kinetic parameters with a variety of inconsistencies from the correct terms summarized above (Figure 1). In most examples, "kinact/KI" has been inappropriately presented as "kinact/Ki", which is an apparent confusion over the use of the dissociation constant (Ki, reflecting only the initial reversible binding step) with the inactivation constant (KI, including binding and covalent bond formation). Additionally, other cases of confusion have arisen where Ki is inappropriately equated to KI being derived from IC50 values. It should be noted that there are instances of authors authentically reporting kinact/Ki values, which are relatively rare. (27,28) Other unclear examples have presented "kinact" as "Kinact", where the lowercase and uppercase differences confuse the term being either a rate or equilibrium constant, respectively. In our experience, such discrepancies can be resolved by evaluating their context with the necessary background knowledge on the methods that have been used to derive these parameters. (12,14)A reasonable and candid opinion of these confusions or misrepresentations of functional parameters may very well be to leave well enough alone since the values obtained are not erroneous or deliberately misleading. Indeed, no intentional harm is done; however, we should take the opportunities to hold ourselves to higher standards in the interest of the field. Where these discrepancies frequently reveal themselves is in conversations with newcomers to medicinal chemistry, namely students and postdocs with training in other fields. For anyone making a sincere effort to afford a complete understanding from the literature, these errors result in intellectual insecurities and propagate inaccuracies into presentations, paper drafts, and other reports that have become increasingly challenging to rectify effectively. Additionally, the conceptional understanding underlying the differences between Ki and KI can be counteracted if the terms defined in the literature are persistently inconsistent. In essence, the details matter significantly for promoting education in our discipline and providing the inspiration for designing improved medicines to treat diverse human diseases. We humbly request that authors, editors, reviewers, and students scrutinize the specifics and definitions/derivations of these various inhibitor parameters to build strong conceptional and mathematical understandings of the nature behind both reversible and irreversible pharmaceutical agents.Author InformationClick to copy section linkSection link copied!Corresponding AuthorDavid E. Heppner, J. Med. Chem. Early Career Board, Department of Chemistry, The State University of New York at Buffalo. Buffalo, New York 14221, United States, https://orcid.org/0000-0002-0722-5160, Email: [email protected]AuthorsBlessing C. Ogboo, Department of Chemistry, The State University of New York at Buffalo. Buffalo, New York 14221, United StatesDaniel A. Urul, AssayQuant Technologies Inc., Marlboro, Massachusetts 01752, United States, https://orcid.org/0000-0003-2932-0369Earl W. May, AssayQuant Technologies Inc., Marlboro, Massachusetts 01752, United StatesErik M. Schaefer, AssayQuant Technologies Inc., Marlboro, Massachusetts 01752, United StatesAndrew S. Murkin, Department of Chemistry, The State University of New York at Buffalo. Buffalo, New York 14221, United States, https://orcid.org/0000-0002-2559-4605Matthias Gehringer, J. Med. Chem. Editorial Advisory Board, Division of Medicinal Chemistry, Institute of Biomedical Engineering, University Hospital Tübingen and Institute of Pharmaceutical Sciences, University of Tübingen. 72076 Tübingen, Germany, https://orcid.org/0000-0003-0163-3419NotesViews expressed in this editorial are those of the authors and not necessarily the views of the ACS.AcknowledgmentsClick to copy section linkSection link copied!We acknowledge generous support from the National Institute of General Medical Sciences of the NIH (R35GM155353-01 to D.E.H.), National Center for Advancing Translational Sciences of the NIH under award number UL1TR001412-08 (BTC K Scholar Award to D.E.H.), startup funds from The State University of New York (to D.E.H.), and the National Science Foundation (CHE-2317422 to A.S.M.). We also acknowledge support from Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy (EXC 2180-390900677 to M.G.) as well as Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) project number 511101075 (to M.G.), and the Deutsche Krebshilfe (German Cancer Aid) − Dr. Mildred Scheel Stiftung für Krebsforschung (to M.G.).ReferencesClick to copy section linkSection link copied! This article references 28 other publications. 1Boike, L.; Henning, N. J.; Nomura, D. K. Advances in covalent drug discovery. Nat. Rev. Drug Discovery 2022, 21 (12), 881– 898, DOI: 10.1038/s41573-022-00542-z Google Scholar1Advances in covalent drug discoveryBoike, Lydia; Henning, Nathaniel J.; Nomura, Daniel K.Nature Reviews Drug Discovery (2022), 21 (12), 881-898CODEN: NRDDAG; ISSN:1474-1776. (Nature Portfolio) A review. Covalent drugs have been used to treat diseases for more than a century, but tools that facilitate the rational design of covalent drugs have emerged more recently. The purposeful addn. of reactive functional groups to existing ligands can enable potent and selective inhibition of target proteins, as demonstrated by the covalent epidermal growth factor receptor (EGFR) and Bruton's tyrosine kinase (BTK) inhibitors used to treat various cancers. Moreover, the identification of covalent ligands through 'electrophile-first' approaches has also led to the discovery of covalent drugs, such as covalent inhibitors for KRAS(G12C) and SARS-CoV-2 main protease. In particular, the discovery of KRAS(G12C) inhibitors validates the use of covalent screening technologies, which have become more powerful and widespread over the past decade. Chemoproteomics platforms have emerged to complement covalent ligand screening and assist in ligand discovery, selectivity profiling and target identification. This Review showcases covalent drug discovery milestones with emphasis on the lessons learned from these programs and how an evolving toolbox of covalent drug discovery techniques facilitates success in this field. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38Xit1Clt7nE&md5=b41441b3a7bc5f2e87bedf243fa43faa2Singh, J. The Ascension of Targeted Covalent Inhibitors. J. Med. Chem. 2022, 65 (8), 5886– 5901, DOI: 10.1021/acs.jmedchem.1c02134 Google Scholar2The Ascension of Targeted Covalent InhibitorsSingh, JuswinderJournal of Medicinal Chemistry (2022), 65 (8), 5886-5901CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society) A review. Perspective. Covalent drugs have made a major impact on human health but until recently were shunned by the pharmaceutical industry over concerns about the potential for toxicity. A resurgence has occurred driven by the clin. success of targeted covalent inhibitors (TCIs), with eight drugs approved over the past decade. The opportunity to create unique drugs by exploiting the covalent mechanism of action has enabled clin. decisive target product profiles to be achieved. TCIs have revolutionized the treatment paradigm for non-small-cell lung cancer and chronic lymphocytic leukemia. This Perspective will highlight the clin. and financial success of this class of drugs and provide early insight into toxicity, a key factor that had hindered progress in the field. Further innovation in the TCI approach, including expanding beyond cysteine-directed electrophiles, kinases, and cancer, highlights the broad opportunity to deliver a new generation of breakthrough therapies. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhtVaitLbL&md5=c7ceaa1fb88ea1c9bc8ae010fc7622653Ferrins, L.; Adams, A. Call for Papers: Exploring Covalent Modulators in Drug Discovery and Chemical Biology. J. Med. Chem. 2023, 66 (16), 10867– 10867, DOI: 10.1021/acs.jmedchem.3c00928 Google ScholarThere is no corresponding record for this reference.4Copeland, R. A.; Pompliano, D. L.; Meek, T. D. Drug–target residence time and its implications for lead optimization. Nat. Rev. Drug Discovery 2006, 5 (9), 730– 739, DOI: 10.1038/nrd2082 Google Scholar4Drug-target residence time and its implications for lead optimizationCopeland, Robert A.; Pompliano, David L.; Meek, Thomas D.Nature Reviews Drug Discovery (2006), 5 (9), 730-739CODEN: NRDDAG; ISSN:1474-1776. (Nature Publishing Group) A review. Much of drug discovery today is predicated on the concept of selective targeting of particular bioactive macromols. by low-mol.-mass drugs. The binding of drugs to their macromol. targets is therefore seen as paramount for pharmacol. activity. In vitro assessment of drug-target interactions is classically quantified in terms of binding parameters such as IC50 or Kd. This article presents an alternative perspective on drug optimization in terms of drug-target binary complex residence time, as quantified by the dissociative half-life of the drug-target binary complex. We describe the potential advantages of long residence time in terms of duration of pharmacol. effect and target selectivity. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XptVCltro%253D&md5=60ede2301584b10ac4e8fa18e1e6d1075Bradshaw, J. M.; McFarland, J. M.; Paavilainen, V. O.; Bisconte, A.; Tam, D.; Phan, V. T.; Romanov, S.; Finkle, D.; Shu, J.; Patel, V. Prolonged and tunable residence time using reversible covalent kinase inhibitors. Nat. Chem. Biol. 2015, 11 (7), 525– 531, DOI: 10.1038/nchembio.1817 Google Scholar5Prolonged and tunable residence time using reversible covalent kinase inhibitorsBradshaw, J. Michael; McFarland, Jesse M.; Paavilainen, Ville O.; Bisconte, Angelina; Tam, Danny; Phan, Vernon T.; Romanov, Sergei; Finkle, David; Shu, Jin; Patel, Vaishali; Ton, Tony; Li, Xiaoyan; Loughhead, David G.; Nunn, Philip A.; Karr, Dane E.; Gerritsen, Mary E.; Funk, Jens Oliver; Owens, Timothy D.; Verner, Erik; Brameld, Ken A.; Hill, Ronald J.; Goldstein, David M.; Taunton, JackNature Chemical Biology (2015), 11 (7), 525-531CODEN: NCBABT; ISSN:1552-4450. (Nature Publishing Group) Drugs with prolonged on-target residence times often show superior efficacy, yet general strategies for optimizing drug-target residence time are lacking. Here the authors made progress toward this elusive goal by targeting a noncatalytic cysteine in Bruton's tyrosine kinase (BTK) with reversible covalent inhibitors. Using an inverted orientation of the cysteine-reactive cyanoacrylamide electrophile, the authors identified potent and selective BTK inhibitors that demonstrated biochem. residence times spanning from minutes to 7 d. An inverted cyanoacrylamide with prolonged residence time in vivo remained bound to BTK for more than 18 h after clearance from the circulation. The inverted cyanoacrylamide strategy was further used to discover fibroblast growth factor receptor (FGFR) kinase inhibitors with residence times of several days, demonstrating the generalizability of the approach. Targeting of noncatalytic cysteines with inverted cyanoacrylamides may serve as a broadly applicable platform that facilitates 'residence time by design', the ability to modulate and improve the duration of target engagement in vivo. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFeju7%252FE&md5=85a73d9ecd62695d03166f7009c68dd86Copeland, R. A. The drug–target residence time model: a 10-year retrospective. Nat. Rev. Drug Discovery 2016, 15 (2), 87– 95, DOI: 10.1038/nrd.2015.18 Google Scholar6The drug-target residence time model: a 10-year retrospectiveCopeland, Robert A.Nature Reviews Drug Discovery (2016), 15 (2), 87-95CODEN: NRDDAG; ISSN:1474-1776. (Nature Publishing Group) The drug-target residence time model was first introduced in 2006 and has been broadly adopted across the chem. biol., biotechnol. and pharmaceutical communities. While traditional in vitro methods view drug-target interactions exclusively in terms of equil. affinity, the residence time model takes into account the conformational dynamics of target macromols. that affect drug binding and dissocn. The key tenet of this model is that the lifetime (or residence time) of the binary drug-target complex, and not the binding affinity per se, dictates much of the in vivo pharmacol. activity. Here, this model is revisited and key applications of it over the past 10 years are highlighted. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVCrurnE&md5=23f4a6973d77804292ff0af6c81358c07Zhou, W.; Ercan, D.; Chen, L.; Yun, C.-H.; Li, D.; Capelletti, M.; Cortot, A. B.; Chirieac, L.; Iacob, R. E.; Padera, R. Novel mutant-selective EGFR kinase inhibitors against EGFR T790M. Nature 2009, 462 (7276), 1070– 1074, DOI: 10.1038/nature08622 Google Scholar7Novel mutant-selective EGFR kinase inhibitors against EGFR T790MZhou, Wenjun; Ercan, Dalia; Chen, Liang; Yun, Cai-Hong; Li, Danan; Capelletti, Marzia; Cortot, Alexis B.; Chirieac, Lucian; Iacob, Roxana E.; Padera, Robert; Engen, John R.; Wong, Kwok-Kin; Eck, Michael J.; Gray, Nathanael S.; Janne, Pasi A.Nature (London, United Kingdom) (2009), 462 (7276), 1070-1074CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group) The clin. efficacy of epidermal growth factor receptor (EGFR) kinase inhibitors in EGFR-mutant non-small-cell lung cancer (NSCLC) is limited by the development of drug-resistance mutations, including the gatekeeper T790M mutation. Strategies targeting EGFR T790M with irreversible inhibitors have had limited success and are assocd. with toxicity due to concurrent inhibition of wild-type EGFR. All current EGFR inhibitors possess a structurally related quinazoline-based core scaffold and were identified as ATP-competitive inhibitors of wild-type EGFR. Here we identify a covalent pyrimidine EGFR inhibitor by screening an irreversible kinase inhibitor library specifically against EGFR T790M. These agents are 30- to 100-fold more potent against EGFR T790M, and up to 100-fold less potent against wild-type EGFR, than quinazoline-based EGFR inhibitors in vitro. They are also effective in murine models of lung cancer driven by EGFR T790M. Co-crystn. studies reveal a structural basis for the increased potency and mutant selectivity of these agents. These mutant-selective irreversible EGFR kinase inhibitors may be clin. more effective and better tolerated than quinazoline-based inhibitors. Our findings demonstrate that functional pharmacol. screens against clin. important mutant kinases represent a powerful strategy to identify new classes of mutant-selective kinase inhibitors. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1SktbvI&md5=9b5d41a2be401c67a4b9f04a41cf17258Hillebrand, L.; Liang, X. J.; Serafim, R. A. M.; Gehringer, M. Emerging and Re-emerging Warheads for Targeted Covalent Inhibitors: An Update. J. Med. Chem. 2024, 67 (10), 7668– 7758, DOI: 10.1021/acs.jmedchem.3c01825 Google ScholarThere is no corresponding record for this reference.9Ray, S.; Murkin, A. S. New Electrophiles and Strategies for Mechanism-Based and Targeted Covalent Inhibitor Design. Biochemistry 2019, 58 (52), 5234– 5244, DOI: 10.1021/acs.biochem.9b00293 Google Scholar9New electrophiles and strategies for mechanism-based and targeted covalent inhibitor designRay, Sneha; Murkin, Andrew S.Biochemistry (2019), 58 (52), 5234-5244CODEN: BICHAW; ISSN:0006-2960. (American Chemical Society) A review. Covalent inhibitors are experiencing a growing resurgence in drug design and are an increasingly useful tool in mol. biol. The ability to attach inhibitors to their targets by a covalent linkage offers pharmacodynamic and pharmacokinetic advantages, but this can also be a liability if undesired off-target reactions are not mitigated. The discovery of new electrophilic groups that react selectively with specific amino acid residues is therefore highly desirable in the design of targeted covalent inhibitors (TCIs). Addnl., the ability to control the reactivity through exploitation of the target enzyme's machinery, as in mechanism-based inhibitors (MBIs), greatly benefits from the discovery of new strategies. This Perspective showcases recent advances in electrophile development and their application in TCIs and MBIs, exhibiting high selectivity for their targets. >> More from SciFinder ®https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXntl2qtL0%253D&md5=26ca570b8a9bbbcec0d7525f2c7ff43910Gehringer, M.; Laufer, S. A. Emerging and Re-Emerging Warheads for Targeted Covalent Inhibitors: Applications in Medicinal Chemistry and Chemical Biology. J. Med. Chem. 2019, 62 (12), 5673– 5724, DOI: 10.1021/acs.jmedchem.8b01153 Google Scholar10Emerging and Re-Emerging Warheads for Targeted Covalent Inhibitors: Applications in Medicinal Chemistry and Chemical BiologyGehringer, Matthias; Laufer, Stefan A.Journal of Medicinal Chemistry (2019), 62 (12), 5673-5724CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society) A review. Targeted covalent inhibitors (TCIs) are designed to bind poorly conserved amino acids by mean