Heavy Membrane-Associated Caspase 3: Identification, Isolation, and Characterization
2000; American Chemical Society; Volume: 39; Issue: 51 Linguagem: Inglês
10.1021/bi001007w
ISSN1943-295X
AutoresJoseph Krebs, Anu Srinivasan, Angela Wong, Kevin J. Tomaselli, Lawrence C. Fritz, Joseph C. Wu,
Tópico(s)Trace Elements in Health
ResumoHeavy membrane preparations from 697 lymphoblastoid cells contain a tightly bound caspase zymogen. This heavy membrane-bound procaspase can be efficiently liberated from membrane preparations using detergents. Alternatively, the procaspase can be rapidly processed and activated from membrane preparations by caspase-1 without detergents. The activated caspase-3 was purified using affinity chromatography and characterized by amino acid sequencing and inhibitor specificity analysis. The sequence indicates that this heavy membrane bound caspase is caspase-3. The kinetic properties and inhibitor binding specificity also show that this purified caspase is enzymologically indistinguishable from cytoplasmic or recombinant caspase-3. However, the N-termini of activated heavy membrane-bound and cytoplasmic caspase-3 are slightly different; peptide sequencing data indicate that the heavy membrane caspase-3 begins at Lys 14, whereas the cytoplasmic enzyme begins at Ser 10. Implications of this structural difference are discussed.
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