THE LOW AND HIGH-MOLECULAR-WEIGHT ACID-PHOSPHATASES IN SHEEP LIVER

Subcellular Localization of high and low Mr acid phosphatases war repo rted in the liver of sheep. Both enzymes were isolated by gel filtrati on on Sephadex G-100. Biochemical properties such as optimal pH, molec ular weight determination, effect of inhibitors and some modifier subs tances on both enzymes were also described. Two isoenzymes of low Mr a cid phosphatase namely Ac Pase A and B were purified to specific activ ity of 27 and 23 U/mg ed protein respectively. The isoenzymes were hom ogeneous on SDS-PAGE, moved as single bands of Mr 18,000 and showed is oelectric points of 6.0 and 5.8 respectively. Both isoenzymes catalyse d the hydrolysis or p. nitro phenyl phosphate and phenyl phosphate, ph osphotyrosine and FMN but at different rates. Ac Pase B showed higher k(m) than Ac Pase A toward O. phosphotyrosine and FMN. Ac Pase B was e ffectively activated by purine compounds whereas Ac Pase A was not No differences in sensitivity to inhibitors or modifier substances betwee n Ac Base A and B were observed.