General Properties of Enzymes
1953; Elsevier BV; Linguagem: Inglês
10.1016/b978-1-4832-3150-1.50008-1
AutoresJames B. Sumner, G. Fred Somers,
Tópico(s)Enzyme Catalysis and Immobilization
ResumoThis chapter focuses on enzymes and their general properties. An enzyme, or ferment, is a definite chemical substance of organic nature, thermolabile and elaborated by plants, animals and microorganisms, and capable of increasing the velocity of a chemical reaction without being used up in the process, or becoming a part of the product formed. Many enzymes are simple proteins, while others, especially those concerned with oxidation, are conjugated proteins, where the apoenzyme or protein part is either loosely or firmly bound to some such prosthetic group as hematin, flavin adenine dinucleotide, riboflavin phosphate, cocarboxylase, and pyridoxal phosphate. Enzymes can be classified into four major groups on the basis of the reactions that they catalyze: (1) enzymes that catalyze the addition or removal of water, (2) enzymes that catalyze the transfer of electrons, (3) enzymes that transfer a radical from one molecule to another, and (4) enzymes that split or form a C—C bond without group transfer.
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