A comparison of the non-specific acid phosphomonoesterase activity in the larva of Phocanema decipiens (Nematoda) with that of the muscle of its host the codfish (Gadus morhua).

The non-specific phosphomonoesterase (enzyme I) extracted from the larva of the codworm (Phocanema decipiens) is different from the enzyme (enzyme II) from the muscle of its host, the codfish (Gadus morhua). The pH optima were 4.0 and 4.5, and the KM values for p-nitrophenyl phosphate hydrolysis were 1.8 mM and 6.5 mM for enzymes I and II respectively. The specific specific activity in units (0.01 mumol/min) per mg protein was 4.80 +/- 0.85 and 0.54 +/- 0.07 for enzymes I and II respectively. The specific activity from uninfected muscles was only 0.39 (SD +/- 0.017) units per mg of protein. Both enzymes were inhibited by NaF, HgCl2, and cysteine but were stimulated by 2-mercaptoethanol. EDTA and iodoacetamide had no effect on enzyme I but enzyme II was activated by EDTA and inhibited by iodoacetamide. Cadmium ions inhibited both the enzymes but a conspicuous feature with enzyme II was in the increase in percentage inhibition by lowering the concentration of CD2+.