Purification and Characterization of a Secreted Purple Phosphatase from Soybean Suspension Cultures
1992; Oxford University Press; Volume: 99; Issue: 2 Linguagem: Inglês
10.1104/pp.99.2.391
ISSN1532-2548
AutoresBrian R. LeBansky, Thomas D. McKnight, Lawrence R. Griffing,
Tópico(s)Microbial Metabolites in Food Biotechnology
ResumoWe purified and partially sequenced a purple (lambda(max) = 556 nanometers) acid phosphatase (APase; EC 3.1.3.2) secreted by soybean (Glycine max) suspension-culture cells. The enzyme is a metalloprotein with a Mn(2+) cofactor. This APase appears to be a glycoprotein with a monomer subunit molecular weight of 58,000 and an active dimer molecular weight of approximately 130,000. The protein has an isoelectric point of about 5.0 and a broad pH optimum centered near 5.5. The purified enzyme, assayed with p-nitrophenyl phosphate as the substrate, has a specific activity of 512 units per milligram protein and a K(m) of approximately 0.3 millimolar; phosphate is a competitive inhibitor with a K(i) of 0.7 millimolar. This APase is similar to one found in soybean seed meal but dissimilar to that found in soybean seedlings.
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