Zur biologischen Oxydation der Oxalsäure. II

Abstract

A highly active enzyme, oxaloxhydrase, was prepared from the moss Hylocomium triquetrum. The moss was washed, dried, powdered, and extracted in the ball mill with 20 vols. H2O for 4-6 hrs. The activity of the enzyme soln. was increased 200 fold by acidification at pH 4, (NH4)2SO4 precipitation and dialysis at 3[degree] for 1-2 days against H2O. The enzyme activity was detd. by the manometric method, the difference between the CO2 formed minus the O2 consumed being measured. The optimum pH for the enzyme activity was 3.2 and all activity was destroyed at 92[degree]. Below pH 3 the enzyme was unstable and between pH 3 and 8, stable. Oxaloxhydrase was a moderately stable lyoenzyme, probably an albumin, and its aqueous soln. was bright yellow. The oxalic acid dehydrogenation with O2 was not affected by HCN, H2S and NaN3. The oxaloxhydrase of seed plants was a typical desmoenzyme. The enzyme from sorrel resembled that obtained from moss in its dehydrogenation function, its strict acceptor specificity and its behavior towards inhibitors, but differed from the latter enzyme in its optimum pH (5-7) and in its destruction temp. (61[degree]). Probably the enzymes had the same prosthetic groups, but different protein components.