Gowda; Rao, Journal of the Indian Chemical Society, 1990, vol. 67, # 5, p. 426 - 428
作者:Gowda、Rao
DOI:——
日期:——
<i>N</i>-Chlorosuccinimide-Promoted Oxidative Decarboxylation of α-Amino Acids in Aqueous Alkaline Medium
作者:M. S. Ramachandran、D. Easwaramoorthy、V. Rajasingh、T. S. Vivekanandam
DOI:10.1246/bcsj.63.2397
日期:1990.8
Kinetics of oxidation of twelve α-amino acids (AA) by N-chlorosuccinimide (NClS) in aqueous alkaline media have been studied and compared with those of N-bromosuccinimide (NBS) oxidation. Analysis of the results shows that the observed rate of oxidation is first-order in [oxidant] and zero-order in [substrate]. The rate of oxidation increases with increase in [OH−]free in [NClS], the exception being the amino acids having β-alkyl substituent such as valine, leucine etc. Perusal of the results shows that NC1S/NBS reacts with α-amino acid anion to produce α-amino acyl hypohalite which then decomposes in the rate-determining step to give the products. The intermediate α-amino acyl hypohalite is identified by UV-visible absorption spectra. Glycine behaves differently from other amino acids in both oxidants. The proposed mechanism is consistent with the observed kinetics.
Enzymatic Synthesis of the Ribosylated Glycyl-Uridine Disaccharide Core of Peptidyl Nucleoside Antibiotics
作者:Zheng Cui、Xiaodong Liu、Jonathan Overbay、Wenlong Cai、Xiachang Wang、Anke Lemke、Daniel Wiegmann、Giuliana Niro、Jon S. Thorson、Christian Ducho、Steven G. Van Lanen
DOI:10.1021/acs.joc.8b00855
日期:2018.7.6
Muraymycins belong to a family of nucleoside antibiotics that have a distinctive disaccharide core consisting of 5-amino-5-deoxyribofuranose (ADR) attached to 6′-N-alkyl-5′-C-glycyluridine (GlyU). Here, we functionally assign and characterize six enzymes from the muraymycin biosynthetic pathway involved in the core assembly that starts from uridine monophosphate (UMP). The biosynthesis is initiated