title: Studies on the interaction between Streptomyces pepsin inhibitor and several acid proteinases by means of a zinc(II)-dye complex as a probe.
abstract: The zinc(II) complex of pyridine-2-azo-p-dimethylaniline is bound to several acid proteinases, at pH 5.0, accompanied by a change is the visible absorption spectrum. Streptomyces pepsin inhibitor, which was discovered by Satoi and Murao (Satoi, S. and Murao, S. (1970) Agric. Biol. Chem. 34, 1265-1267 and Satoi, S. and Murao, S. (1971) Agric. Biol. Chem. 35, 1482-1487), is also bound to acid proteinases. Spectrophotometric studies with ten acid proteinases from different sources have revealed that in several acid proteinases, zinc(II)-pyridine-2-azo-p-dimethylaniline is released from the enzyme by the inhibitor, while some acid proteinase forms a quaternary complex, zinc(II)-pyridine-2-azo-p-dimethylaniline-inhibitor-enzyme. It is speculated that zinc(II)-pyridine-2-azo-p-dimethylaniline is bound to two catalytic carboxylate groups in the active site of the acid proteinases and the inhibitor is bound mainly to the substrate-binding site of the enzymes. The binding of the inhibitor may overlap the catalytic site completely or partially. The degree of overlapping is characteristic of the kind of acid proteinases.
mesh_terms: D001230:Aspergillus / Q000201:enzymology; D001234:Aspergillus niger / Q000201:enzymology; D001426:Bacterial Proteins / Q000494:pharmacology; D001665:Binding Sites; D004396:Coloring Agents; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D003904:Mitosporic Fungi / Q000201:enzymology; D008970:Molecular Weight; D010434:Pepsin A / Q000037:antagonists & inhibitors*; D010447:Peptide Hydrolases / Q000378:metabolism; D011485:Protein Binding; D012233:Rhizopus / Q000201:enzymology; D012248:Rhodotorula / Q000201:enzymology; D013045:Species Specificity; D013053:Spectrophotometry; D013302:Streptomyces / Q000032:analysis*; D015032:Zinc
chemical_list: D001426:Bacterial Proteins; D004396:Coloring Agents; D010447:Peptide Hydrolases; D010434:Pepsin A; D015032:Zinc