The protease produced by Mucor pusillus was recovered from a wheat bran medium by treatment with ammonium sulfate, ethyl alcohol, gel filtration and ionexchange chromatography. The yield of the enzyme was 55 %. The overall increase in the specific activity of the protease was 34-fold. The purified protease was most active at pH 3.8 and 5.6 against hemoglobin and casein, respectively. Optimal hydrolysis of casein was observed at 55 C. The enzyme was stable from pH 3.0 to 6.0. Enzyme inactivated by metal ions was reactivated by ethylenediaminetetraacetate and o-phenanthroline. Reducing agents and thiol poisons had no effect on the protease, suggesting that free sulfhydryl groups were not required for enzyme activity. Diisopropyl fluorophosphate did not inhibit the protease, indicating the probable absence of serine in the active center. The Michaelis-Menten constant for casein was 0.357%. Electrophoretic analysis of active protein recovered by ion-exchange chromatography showed that the protease preparation was homogeneous.

No abstract

No abstract

Pepsin rapidly decreases the viscosity of a glutenin dispersion having an acid reaction and rapidly increases -the amount of water-soluble fragments.The molecular weight of the solubilked fragments, estimated by the gel-filtration method, indicates that most of the fragments are large and have:molecular weights greater than 10,000.A comparison of data obtained by gel filtrtition and by determination of terminal amino acids in pepsin hydrolysates of glutenin indicates that cleavage of a few peptide bonds rapidly produces these large molecular polypeptides from glutenin. Further pepsin action causes a substantial increase in small peptide fragments.

No abstract