Ruminal Microbial Metabolism of Peptides and Amino Acids

Variations in the uptake and metabolism of peptides and amino acids by mixed ruminal bacteria in vitro.

Mixed ruminal bacteria, isolated from sheep (Q and W) fed a concentrate and hay diet, were anaerobically incubated with either 14C-peptides or 14C-amino acids. Experiment 1 showed that uptake of both 14C-labeled substrates was rapid, but the rate for amino acids was twofold greater than for peptides (molecular weight, 1,000 to 200) initially but was similar after 10 min. Experiment 2 demonstrat...

Fermentation of peptides and amino acids by a monensin-sensitive ruminal Peptostreptococcus.

A monensin-sensitive ruminal peptostreptococcus was able to grow rapidly (growth rate of 0.5/h) on an enzymatic hydrolysate of casein, but less than 23% of the amino acid nitrogen was ever utilized. When an acid hydrolysate was substituted for the enzymatic digest, more than 31% of the nitrogen was converted to ammonia and cell protein. Coculture experiments and synergisms with peptide-degradin...

Amino Acids, Amines and Peptides of Ram

Epididymal semen was obtained from rams with a fistula present in the vas deferens (Tadmor & Schindler, 1966). It was deproteinized immediately, and the protein-free clear supernatant evaporated to dryness in vacuo at a temperature not exceeding 55\s=deg\C. The residue was taken up with about 10 ml water, and the solution thus obtained used for determination of both amines and amino acids. For ...

Nucleophilicities of amino acids and peptides.

The kinetics of the reactions of amino acids with stabilized diarylcarbenium ions (Ar(2)CH(+)) have been studied photometrically in aqueous solution at variable pH. In the range of 10.5 < pH < 12, the amino acids react much faster than the competing nucleophiles hydroxide and water. Though the pK(aH) values of the amino acids vary by almost four units, the nucleophilic reactivities of all prima...

Complex Salts of Amino Acids and Peptides