Function of pyridoxal phosphate in desulfhydrase systems of Proteus morganii.

It has been reported (1) that cystine is metabolized by resting cells of Proteus vulgaris and Proteus morganii to pyruvate, ammonia, and hydrogen sulfide, Toluene-killed cells of P. morganii also carried out the reaction and to a lesser degree attacked homocysteine, yielding hydrogen sulfide, ammonia, and some unidentified product. Inasmuch as the use of toluene-killed cells may not obviate entirely considerations of permeability, it was deemed essential to study the reactions with cell-free enzymatic preparations. The present paper describes some of the characteristics of cell-free desulfhydrases in P. morganii.