Purification and properties of vacuolar membrane proton-translocating inorganic pyrophosphatase from mung bean

摘要: Inorganic pyrophosphatase was purified from the vacuolar membrane of mung bean hypocotyl tissue by solubilization with lysophosphatidylcholine and QAE-Toyopearl chromatography. The molecular mass on sodium dodecyl sulfate-polyacrylamide gel electrophoresis 73,000 daltons. Among amino-terminal first 30 amino acids are 25 nonpolar hydrophobic residues. For maximum activity, required 1 mM Mg2+ 50 K+. enzyme reaction stimulated exogenous phospholipid in presence detergent. Excess pyrophosphate as well excess magnesium inhibited pyrophosphatase. strongly ATP, GTP, CTP at 2 mM, inhibition reversed increasing concentration. An antibody preparation raised a rabbit against both reactions hydrolysis pyrophosphate-dependent H+ translocation tonoplast vesicles. N,N'-Dicyclohexylcarbodiimide became bound to hydrolysis. It is concluded that 73-kDa protein functions an H+-translocating inorganic