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：1972
卷号：69
期号：3
页码：662-666
DOI：10.1073/pnas.69.3.662
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：In the presence of N[α],N{varepsilon}-diacetyl-L-Lys-D-Ala-D-Ala as donor, and either D-[14C]alanine, [14C]-glycine, or meso-[3H]diaminopimelic acid as acceptor, the DD carboxypeptidases from Streptomyces R61 and R39 catalyze a transpeptidation reaction with the release of terminal D-alanine from the donor and the formation of either N[α],N{varepsilon}-diacetyl-L-Lys-D-Ala-D-[14C]Ala, N[α],N{varepsilon}-diacetyl-L-Lys-D-Ala-[14C] Gly, or N[α],N{varepsilon}-diacetyl-L-Lys-D-Ala-D-meso- [3H]diaminopimelic acid. The reaction appears to be a true transpeptidation, and is not simply a "reversal of hydrolysis". Transpeptidation is inhibited by pencillin at concentrations that inhibit hydrolysis (carboxypeptidase action) of the donor peptide. There are differences in the specificity profiles of the Streptomyces enzymes for acceptor molecules:only the R61 enzyme used [14C]Gly-Gly as acceptor; transfer of N[α],N{varepsilon}-diacetyl-L-Lys-D-Ala to this acceptor resulted in the formation of N[α],N{varepsilon}-diacetyl-Lys-D-Ala-[14C] Gly-Gly, with the synthesis of a (D-Ala-Gly) peptide bond in an endoposition.
