Studies on kinetic properties of non-specific phosphomonoesterases in the sheep nematode, Bunostomum trigonocephalum Rudolphi, 1808.

The maximum activity (Vmax) of acid phosphomonoesterase (E.C.3.1.3.2.) at pH 5.5 and 37 degrees C was found to be 2.68 +/- 0.25 and 3.85 +/- 0.24 mu moles phenol mg protein-1 min-1 in male and female Bunostomum trigonocephalum, respectively. The Vmax of alkaline phosphomonoesterase (E.C.3.1.3.1) at pH 10.0 and 37 degrees C was 0.75 +/- 0.04 and 1.15 +/- 0.05 mu moles phenol mg protein-1 min-1 in male and female B. trigonocephalum, respectively. The Michaelis constant (Km) values were 10.25 mM and 11.76 mM for acid and 8.69 mM and 9.09 mM for alkaline phosphomonoesterase in male and female worms, respectively. Enzymal activities were optimum at 7.0 and 9.0% enzyme concentrations, at incubation periods of 60 and 20 min and at temperatures of 50 and 45 degrees C for acid and alkaline phosphomonoesterases, respectively. Dialysis in distilled water decreased the activity of both enzymes, while only acid phosphomonoesterase activity increased in citrate buffer (pH 5.5) and alkaline phosphomonoesterase activity in carbonate buffer (pH 10.0).