The interaction of L-ascorbic acid with the active center of myrosinase.
Biochim Biophys Acta, 1979/4/12;567(2):384-91.
PMID: 109123
Abstract
Only L-ascorbic acid activated plant myrosinase (thioglucoside glucohydrolase, EC 3.2.3.1), whereas ascorbic acid analogs did not. The enzyme protein was conformationally changed by the addition of L-ascorbic acid to the spectrophotometric analysis, approx. 1.5 amino residues appeared on the surface of the enzyme and about 2.3 tryptophan residues were buried in the molecule when 1 mM L-ascorbic acid was added. Optimum temperature for the myrosinase activity was approx. 55 degrees C without L-ascorbic acid, but with L-ascorbic acid it was about 35 degrees C; that for beta-glucosidase activity was the same (55 degrees C) with or without L-ascorbic acid. The effect of chemical modification of the functional groups of myrosinase on the interaction of L-ascorbic acid was investigated and the interaction of L-ascorbic acid with the active center of the enzyme is proposed.
MeSH terms
2-Hydroxy-5-nitrobenzyl Bromide; Ascorbic Acid; Binding Sites; Glycoside Hydrolases; Mercuribenzoates; Plants; Protein Conformation; Temperature; Thioglucosides; Tropanes; beta-Glucosidase
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