Abstract: | Protease B has been isolated from dormant cotton seeds by fractionation with ammonium sulfate, ion-exchange chromatography on CM-cellulose, and gel filtration through Acrilex P-10 and Sephadex G-75, with 128-fold purification. The enzyme exists in dimeric and monomeric forms. According to the results of gel filtration, their molecular weights are 72,000 and 36,000, respectively. The enzyme consists of a single polypeptide chain including sugars. The N-terminal amino acid of protease B is alanine. The enzyme possesses proteolytic activity in the pH range from 4 to 6. |