Analysis of peptide metabolism by ruminal microorganisms.
Methods were developed for the determination of oligoalanine and other short-chain peptides and peptide analogs in ruminal fluid by using reverse-phase high-pressure liquid chromatography. Chromatographic analysis of the breakdown of (Ala)3 and (Ala)4 in ruminal fluid in vitro revealed that the predominant mechanism of hydrolysis was a dipeptidyl peptidase-like activity. Hydrolysis proceeded from the N terminal of the peptide chain; N-acetyl-(Ala)3 was broken down at 11% of the rate of breakdown of (Ala)3 or (Ala)3-p-nitroanilide. (Ala)2-p-nitroanilide was hydrolyzed most rapidly of the arylamide substrates tested, but fluorogenic 4-methoxy-2-naphthylamide (MNA) compounds were more convenient and potentially more versatile substrates than p-nitroanilides. Gly-Arg-MNA was the most rapidly hydrolyzed dipeptidyl peptidase substrate, suggesting that ruminal peptidase activity was predominantly of a type I specificity.
Wallace
R J
RJ
Rowett Research Institute, Aberdeen, United Kingdom.
McKain
N
N
D000409:Alanine / Q000378:metabolism; D000626:Aminopeptidases / Q000302:isolation & purification / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D006868:Hydrolysis; D009842:Oligopeptides / Q000378:metabolism*; D012417:Rumen / Q000201:enzymology / Q000378:metabolism / Q000382:microbiology*; D012756:Sheep; D013379:Substrate Specificity
D009842:Oligopeptides; D000626:Aminopeptidases; D000409:Alanine