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A Practical Introduction to Structure, Mechanism, and Data Analysis - Part 6

Phản ứng enzyme hoạt động thủy phân minh họa bằng các protease serine là một trong nhiều loại trái phiếu chia tách và phản ứng hình thành liên kết xúc tác bởi các enzyme. Từ các nghiên cứu sớm nhất của các protein này, các nhà khoa học đã cố gắng phân loại chúng bởi tính chất của phản ứng mà họ cung cấp. Tên nhóm đã được giao cho các enzym chia sẻ reactivities phổ biế | 184 CHEMICAL MECHANISMS IN ENZYME CATALYSIS general types of interaction illustrated with the serine proteases also govern substrate binding and chemical transformations in all the enzymes nature has devised. 6.5 ENZYMATIC REACTION NOMENCLATURE The hydrolytic activity illustrated by the serine proteases is but one of a wide variety of bond cleavage and bond formation reactions catalyzed by enzymes. From the earliest studies of these proteins scientists have attempted to categorize them by the nature of the reactions they provide. Group names have been assigned to enzymes that share common reactivities. For example protease and proteinase are used to collectively refer to enzymes that hydrolyze peptide bonds. Common names for particular enzymes are not always universally used however and their application in individual cases can lead to confusion. For example there is a metalloproteinase known by the common names stromelysin MMP-3 for matrix metalloproteinase number 3 transin and proteoglycanase. Some workers refer to this enzyme as stromelysin others call it MMP-3 and still others call it transin or proteog-lycanase. A newcomer to the metalloproteinase field could be quite frustrated by this confusing nomenclature. For this reason the International Union of Pure and Applied Chemistry IUPAC formed the Enzyme Commission EC to develop a systematic numerical nomenclature for enzymes. While most workers still use common names for the enzymes they are working with literature references should always include the IUPAC EC designations which have been universally accepted to let the reader know precisely what enzymes are being discussed. The EC classifications are based on the reactions that enzymes catalyze. Six general categories have been defined as summarized in Table 6.4. Within each of these broad categories the enzymes are further differentiated by a second number that more specifically defines the substrates on which they act. For example 11 types of hydrolase .