CHARACTERIZATION OF HIGH-MOLECULAR-WEIGHT AND LOW-MOLECULAR-WEIGHT ZINC-DEPENDENT ACID-PHOSPHATASES IN BOVINE LIVER

We have purified two forms of Zn2+-dependent acid phosphatase (Zn2+-AP ase) from bovine liver, both of which require Zn2+ to hydrolyze the su bstrate p-nitrophenyl phosphate in an acidic environment. The apparent molecular weights of these two forms of Zn2+-APase were estimated to be about 100000 and 62000 by gel filtration, and about 44000 and 31000 by polyacrylamide gel electrophoresis in the presence of sodium dodec yl sulfate, respectively. The low-molecular weight (LMW) Zn2+-APase ca talyzed the hydrolysis of myo-inositol-1-phosphate in the presence of 3 mM Mg2+ at physiological pH, but the high-molecular weight (HMW) enz yme did not. The LMW- Zn2+-APase of bovine liver was recognized by pol yclonal antibodies developed against the Zn2+-APase of bovine brain, b ut the HMW-Zn2+-APase was not.