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THE PEPTASE, LIPASE, AND INVERTASE OF HEMOLYTIC STREPTOCOCCUS

1922; Rockefeller University Press; Volume: 35; Issue: 6 Linguagem: Inglês

10.1084/jem.35.6.823

1540-9538

Franklin A. Stevens, Randolph West,

Biochemical and Structural Characterization

1. A method has been outlined by which the enzymes of hemolytic streptococcus may be extracted with comparative ease. 2. The peptolytic enzyme is active between pH 4.4 and 8.7 with an optimum action at pH 7.2. It is destroyed in neutral phosphate solution at a temperature of 57 degrees C. continued for 10 minutes and at pH 5.0 deteriorates slowly at 37 degrees C. Concentration experiments with solutions of the enzyme have shown that it resembles other enzymes. It is exceedingly susceptible to chloroform and its action is inhibited by dilutions of gentian violet. Casein is attacked but serum albumin is not digested after 3 days at 37 degrees C. 3. The invertase is active between approximately pH 5.0 and 8.0 with an optimum of pH 7.0. It is destroyed by a temperature of 52 degrees C. continued 10 minutes at an acid concentration of pH 7.0, or after 6 hours at 37 degrees C. at pH 5.0. At this acidity it is more susceptible to heat than the peptase. 4. The lipase is active above pH 5.6. The greatest activity was observed at pH 7.9. It is completely destroyed after heating to temperatures over 55 degrees C. for 10 minutes and resembles the invertase in its susceptibility to acid.