ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Quantum yields for the inactivation of crystalline swine pepsin have been determined as a function of pH at 2537 A. The quantum yield is near a minimum at pH 4.08, at which point a value of 0.0019 was found, rises rapidly above pH 6, and shows a slight maximum near pH 2.7. The maximum is more pronounced with polychromatic light. The quantum yield (at pH 2.01) was found to be the same with either hemoglobin or casein as a substrate. Urea had no effect on the quantum yield although urea alone, 7 M, inactivates pepsin at an appreciable rate. Urea and light denaturation do not modify the absorption spectrum of pepsin in the same way. The data of Gates has been recalculated; it shows an increase of quantum yields with decreasing wave length. It has been concluded, from experiments with model substances, that inactivation can occur by the absorption of a quantum by any aromatic group in pepsin.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1949.120040104
