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The activity of pepsin-albumin films

1953; Elsevier BV; Volume: 43; Issue: 2 Linguagem: Inglês

10.1016/0003-9861(53)90138-6

1096-0384

Daniel Mazia, Teru HAYASHI,

Enzyme Production and Characterization

Abstract 1. 1. Active pepsin-albumin fibers may be prepared by spreading monolayers from mixed solutions at pH 4, and compressing the film into a fiber. 2. 2. Enzyme activity of the compressed films may be measured by microscopic observation of self-digestion in acid solution and by microdetermination of trichloroacetic acid-soluble products of proteolysis. 3. 3. The pH optimum of the system is 1.5. 4. 4. Rates of digestion in this “solid phase” system are compared with rates in corresponding systems where the enzyme is in solution. The activity of the former is higher than predicted from its content of enzyme and substrate, even without allowing for supposed “surface denaturation”. 5. 5. The rate of digestion depends on the ratio of substrate to enzyme in the film, within certain limits. 6. 6. The activity of the compressed films depends on the pressure at which they were spread. 7. 7. The relation between surface spreading and enzyme activity is discussed. The evidence suggests that we are dealing with B-films (Joly) of partially unfolded protein and that a degree of unfolding that leads to loss of solubility does not necessarily destroy enzyme activity. 8. 8. The biological implications of enzyme reactions in solid, structured systems are discussed.