Alkaline phosphatase from Nocardia asteroides

Intracellular alkaline phosphatase (Apase) produced during growth of Nocardia asteroides in dephosphated nutrient broth supplemented with 1% glucose and some properties of the purified enzyme were studied. Filamentous cells of N. asteroides synthetized the Apase in high yields (7.0 x 10(3) units/mg cell protein) during exponential growth phase. The intracellular level dropped drastically and the extracellular amounts increased during stationary phase, probably due to the loss of the enzyme in the medium because of the fragmentation of the filamentous cells into rod-like and spherical forms and/or due to cell lysis. The purified enzyme showed typical Apase activity with optimal pH at 10 and optimal temperature at 37 degrees C. The Km of the enzyme for p-nitrophenyl phosphate was close to the value reported for Apase from other sources. Other properties of the enzyme which resembled those from other species included respectively the uncompetitive, non-competitive and competitive inhibition of L-phenylalanine, urea and inorganic phosphate. The effect of these compounds on the enzyme may be useful in the regulation of Apase activity in vivo and hence may play a vitalrole during morpho genesis of N. asteroides.