Abstract
Two enzymes, nitrile hydratase and amidase, which participate in the conversion of trans-1, 4-dicyanocyclohexane (tDCC) to trans-4-cyanocyclohexane-1-carboxylic acid (tMCC), a tranexamic acid intermediate, were purified and characterized. Nitrile hydratase was obtained in a homogeneous state. The molecular weight of the native enzyme was 61, 400 and that of the subunit 26.900, indicating a dimer structure. Valeronitrile and butyronitrile were good substrates for the enzyme. The enzyme could also hydrate benzonitrile, p-hydroxybenzonitrile and 4-cyanobenzoic acid. tDCC was exclusively hydrated to trans-4-cyanocyclohexane-1-carboxyamide (tMCMA), further hydration of the nitrile group of tMCMA and t-MCC not being observed. The presence of py rroloquinoline quinone in the enzyme was confirmed. The presence of iron was also confirmed. The amidase of the strain was also purified. The latter enzyme could hydrate tMCMA, yielding tMCC. The enzyme was highly resistant to SH reagents.
