Adachi H, Tsujimoto M
Suntory Institute for Biomedical Research, Osaka.
J Biochem. 1995 Sep;118(3):555-61. doi: 10.1093/oxfordjournals.jbchem.a124945.
The gene encoding dipeptidase was cloned from Acinetobacter calcoaceticus ATC 23055. Determination of the nucleotide sequence revealed that the gene had an open reading flame of 1,050 bp coding a protein of 350 amino acids. The deduced amino acid sequence showed 48.8% similarity to human renal dipeptidases and conserved two amino acid residues identified in human and pig renal dipeptidases as essential ones for the catalytic activity. Purified recombinant enzyme expressed in Escherichia coli did not hydrolyze the unsaturated dipeptide, glycyldehydrophenylalanine. On the other hand, it preferentially hydrolyzed dipeptides having a D-amino acid, when compared with those having an L-amino acid at the C-terminal. Furthermore, it could not hydrolyze tripeptides. These results indicate that the dipeptidase produced by A. calcoaceticus ATC 23055 has a unique substrate specificity and preferentially hydrolyzes dipeptides having a D-amino acid at the C-terminal.
从醋酸钙不动杆菌ATC 23055中克隆了编码二肽酶的基因。核苷酸序列测定表明，该基因有一个1050 bp的开放阅读框，编码一个由350个氨基酸组成的蛋白质。推导的氨基酸序列与人类肾二肽酶有48.8%的相似性，并保留了在人类和猪肾二肽酶中确定为催化活性所必需的两个氨基酸残基。在大肠杆菌中表达的纯化重组酶不水解不饱和二肽甘氨酰脱氢苯丙氨酸。另一方面，与在C末端具有L-氨基酸的二肽相比，它优先水解具有D-氨基酸的二肽。此外，它不能水解三肽。这些结果表明，醋酸钙不动杆菌ATC 23055产生的二肽酶具有独特的底物特异性，优先水解在C末端具有D-氨基酸的二肽。
