Stereochemistry and mechanism of the conversion of 5-aminolaevulinic acid into porphobilinogen catalysed by porphobilinogen synthaseElectronic supplementary information (ESI) available: purification and assay protocols and plots of enzymic activity vs. substrate concentration. See http://www.rsc.org/suppdata/ob/b3/b302509h/
Deuterium isotope effects on porphobilinogen synthesis catalysed by 5-aminolaevulinic acid dehydratase
摘要:
Deuteriation of 5-aminolaevulinic acid (ALA) at C-5 has no effect on the rate of porphobilinogen synthesis by ALA dehydratase from Bacillus subtilis but deuteriation at C-3 gave isotope effects on k(cat) and k(cat)/K-M of 3.4 and 2.3 respectively. Reisolated ALA after 50% reaction shows no significant loss of deuterium at C-3, indicating that it is probably the first deprotonation at this carbon which is rate-determining. Copyright (C) 1996 Elsevier Science Ltd