Peptidohydrolases of Soybean Root Nodules

Authors

Nasir S. A. Malik, University of Nebraska - Lincoln
N. E. Pfeiffer, University of Nebraska-Lincoln
D. R. Williams, University of Nebraska-Lincoln
Fred W. Wagner, University of Nebraska-LincolnFollow

Date of this Version

1981

Citation

Plant Physiol. (1981) 68, 386-392

Abstract

Nodule extracts prepared from Glycine max var Woodworth possessed endopeptidase, aminoptidase, and carboxypeptidase actiities. Three distinct endopeptidase activities could be resolved by disc-gel electrophoresis at pH 8.8. According to their order of increasing electrophoretic mobility, the first of these enzymes hydrolyzed azocasein and n-benzoyl-LLeu-β-naphthylamide, while the second hydrolyzed n-benzoyl-L-Arg-/8- naphthylamine (Bz-L-Arg-/βNA), n-benzoyl-L-Arg-β-nitroanilide (Bz-L-Arg-βNA), and azocasein. The third endopeptidase hydrolyzed Bz-L-Arg-βNA, Bz-L-Arg-βNA, and hemoglobin. Fractions of these enzymes extracted from electrophoresis gels were shown to have pH optima from 7.5 to 9.8. AU of the endopeptidases were completely inhibited by diisopropylphosphorofluoridate, demonstrating that they were serine proteases.