found to be an excellent coupling reagent having a water-soluble property and a high reactivity; it worked as satisfactory as usual activeesters in regard to the reactivity, product purity, and racemization. The marked advantage of the HODMSP·MeSO4− activeester method was the fact that bifunctional residues such as Arg, Lys, Cys, and Tyr could be selectively acylated when the pH of the reaction mixture
Chemical isotope labeling-assisted liquid chromatography-mass spectrometry enables sensitive and accurate determination of dipeptides and tripeptides in complex biological samples
作者:Feng-Qing Huang、Yu Wang、Ji-Wen Wang、Dai Yang、Shi-Lei Wang、Yuan-Ming Fan、Raphael N. Alolga、Lian-Wen Qi
DOI:10.1016/j.cclet.2024.109670
日期:2024.2
their unique features and diverse biological functions. Achieving rapid separation and accurate quantification, however, remains a challenge because of their low abundance and the co-existence of numerous structural isomers. In this study, we developed a novel approach using isotopechemical labeling for ultrasensitive determination of di/tripeptides in biologicalsamples. We successfully synthesized a
Structure, Mechanism, and Substrate Profile for Sco3058: The Closest Bacterial Homologue to Human Renal Dipeptidase,
作者:Jennifer A. Cummings、Tinh T. Nguyen、Alexander A. Fedorov、Peter Kolb、Chengfu Xu、Elena V. Fedorov、Brian K. Shoichet、David P. Barondeau、Steven C. Almo、Frank M. Raushel
DOI:10.1021/bi901935y
日期:2010.1.26
Human renal dipeptidase, an enzyme associated With glutathione metabolism and the hydrolysis of beta-lactams, is similar in sequence to a cluster of similar to 400 microbial proteins currently annotated as nonspecific dipeptidases within the amidohydrolase superfamily. The closest homologue to the human renal dipeptidase from a Fully sequenced microbe is Sco3058 from Streptomyces coelicolor. Dipeptide Substrates of Sco3058 were identified by screening a comprehensive series Of L-Xaa-L-Xaa, L-Xaa-D-Xaa, and D-Xaa-L-Xaa dipeptide libraries. The substrate specificity profile shows that Sco3058 hydrolyzes a broad range of dipeptides with a marked preference for all L-amino acid at the N-terminus and a D-amino acid at the C-terminus. The best Substrate identified was L-Arg-D-Asp (k(eat)/K-m = 7.6 x 10(5) M-1 s(-1)). The three-dimensional structure of Sco3058 was determined in the absence and presence of the inhibitors citrate and a phosphinate mimic Of L-Ala-D-Asp. The enzyme folds as (beta/alpha)(8) barrel, and two zinc Ions are bound in the active site. Site-directed mutagenesis was used to probe the importance of specific residues that have direct interactions with the substrate analogues in the active site (Asp-22, His-150, Arg-223, and Asp-320). The solvent viscosity and kinetic effects of D2O indicate that Substrate binding is relatively sticky and that proton transfers do not occur during the rate-limiting step. A bell-shaped pH-rate profile for k(cat) and k(cat)/k(m) indicated that one group needs to he deprotonated and a second group Must be protonated for optimal turnover. Computational docking of high-energy intermediate forms Of L/D-Ala-L/D-Ala to the three-dimensional Structure of Sco3058 identified the Structural determinants for the stereochemical preferences for Substrate binding and turnover.
Consden; Gordon; Martin, Biochemical Journal, 1949, vol. 44, p. 557
作者:Consden、Gordon、Martin
DOI:——
日期:——
HETEROCYCLIC DERIVATIVES AND THEIR USE AS INTEGRIN INHIBITORS