Measurement of proteinase B activity in crude yeast extracts: A novel procedure of activation using pepsin

✍ Scribed by Jaime Schwencke

• Book ID: 102983500
• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 591 KB
• Volume: 118
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(81)90588-1

✦ Synopsis

Proteinase

B activity in crude yeast extract is difficult to detect, unless the firmly bound peptide inhibitor is previously inactivated. Methods currently used to accomplish this inactivation suffer from serious limitations, particularly when applied to crude extracts obtained from yeast grown in complete media. These limitations are discussed on the basis of the kinetics of activation.

A novel procedure to unmask proteinase B activity, based on pepsin treatment of crude extracts, is described. Specific activity of proteinase B, determined after pepsin A treatment, is always two to three times higher than that obtained by other methods. The method proposed is simple, reliable, and can be applied to crude extracts stored at -20°C for up to 1 week, repeatedly giving the same specific activity for proteinase B.