BREAKDOWN OF DIFFERENT PEPTIDES BY PREVOTELLA (BACTEROIDES) RUMINICOLA AND MIXED MICROORGANISMS FROM THE SHEEP RUMEN

Several di-, tri-, and oligopeptides were incubated individually in vi tro with rumen fluid from two sheep receiving a mixed grass hay/concen trate diet and with washed cells of Prevotella (formerly Bacteroides) ruminicola M384 and P. ruminicola B(1)4. The rates of breakdown of mos t peptides were similar in the rumen fluid from the two sheep. Acidic and proline-containing peptides tended to be more slowly degraded than neutral or basic peptides. The dipeptide at the N-terminus of higher peptides was observed as an early product of hydrolysis, confirming th at a dipeptidyl aminopeptidase type of activity was present. The relat ive rates of breakdown of dipeptides by P. ruminicola were different f rom that of rumen fluid, but the hydrolysis of higher peptides followe d a similar pattern, and dipeptides from the N-terminus were detected as early products.