期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1975
卷号：72
期号：5
页码：1666-1670
DOI：10.1073/pnas.72.5.1666
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The amino-acid sequence of bovine carboxypeptidase B [peptidyl-L-lysine(-L-arginine)hydrolase, EC 3.4.12.3 ] has been determined using the heavy and light chains of the enzyme isolated from spontaneously activated pancreatic juice. Comparison of the sequence with that of carboxypeptidase A shows that the two enzymes are homologous (49% identity) and that all but one of the functional residues identified in carboxypeptidase A occur in corresponding loci in carboxypeptidase B (peptidyl-L-amino acid hydrolase, EC 3.4.12.2 ). The exception is the replacement of Ile-255 at the bottom of the substrate binding pocket of carboxypeptidase A, by aspartic acid in carboxypeptidase B. This single change can account for the difference in specificity of the two enzymes.
