RT Journal Article SR Electronic(1) A1 Patni, N. J. A1 Aaronson, S.YR 1974 T1 Partial Characterization of the Intra- and Extracellular Acid Phosphatase of an Alga, Ochromonas danica JF Microbiology, VO 83 IS 1 SP 9 OP 20 DO https://doi.org/10.1099/00221287-83-1-9 PB Microbiology Society, SN 1465-2080, AB SUMMARY: Intra- and extracellular acid phosphatases were purified 88- and 65-fold respectively from photoheterotrophic Ochromonas danica Pringsheim. The purified enzymes differed in heat inactivation, substrate specificity, and inhibition by several divalent cations and NaF. Intracellular enzyme lost only 30 % of its activity by heating at 60 °C for 200 min whereas the extracellular enzyme lost 80 %. Both enzymes were active over a broad pH range from 2·2 to 5·2 and had an optimum pH of 4·8. Both had broad substrate specificity and differed in their relative ability to hydrolyse β -glycerophosphate, phenolphthalein diphosphate, glucose-1 -phosphate, fructose-1,6-diphosphate, ADP and ATP. Both were inhibited by Co2+, Zn2+, Hg2+, Fe3+, arsenate, tartrate and fluoroacetate but differed in their inhibition by Cu2+, Hg2+ and NaF. Intracellular acid phosphatase was more susceptible to inhibition by Hg2+ and NaF, while extracellular acid phosphatase was more susceptible to inhibition by Cu2+. pChloromercuribenzoate and urea had no effect on either enzyme’s activity. EDTA stimulated the activity of both enzymes. The Km for the intra- and the extracellular enzymes was 0·5 and 0·33 mm respectively with p-nitrophenyl phosphate as the substrate., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-83-1-9