Effect of acetohydroxamic acid on rumen urease activity in vitro.
Acetohydroxamic acid at a concentration of 1 X 10(-6) M, 6 X 10(-5) M, and 1 X 10(-3) M inhibited urease of intact rumen microbes in vitro by 11%, 50%, and 74%. Inhibition of rumen urease by the acid reached equilibrium state, unlike jack bean urease. Inhibition was maximum over a broad range of pH (8 to 10) and it did not resemble the pH activity profile of rumen urease. Sulfhydryl compounds did not reverse the inhibition; however, addition of these compounds prior to acetohydroxamic acid addition prevented inhibition. The nature of inhibition was noncompetitive with inhibitor constant 4.8 X 10(-5) M. Acetohydroxamic acid at a concentration that produced 50% urease inhibition did not affect rumen cellulase and proteolytic enzymes in vitro. The complex of acetohydroxamic acid-rumen urease is dissociable on dialysis.
D000818:Animals; D002020:Buffaloes; D006877:Hydroxamic Acids / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D066298:In Vitro Techniques; D012417:Rumen / Q000201:enzymology*; D013438:Sulfhydryl Compounds / Q000494:pharmacology; D014510:Urease / Q000037:antagonists & inhibitors*
D006877:Hydroxamic Acids; D013438:Sulfhydryl Compounds; C006358:acetohydroxamic acid; D014510:Urease