%0 Journal Article %A Wimpenny, J. W. T. %T The uptake and fate of Isoniazid in Mycobacterium tuberculosis var. bovis BCG %D 1967 %J Microbiology, %V 47 %N 3 %P 389-403 %@ 1465-2080 %R https://doi.org/10.1099/00221287-47-3-389 %I Microbiology Society, %X SUMMARY The incorporation of 14C INH into sensitive and resistant bacteria has been investigated. Only organisms susceptible to INH took up the drug. Uptake was irreversible and became saturated at higher INH concentrations. Uptake was heat-labile, KCN-sensitive, partially inhibited by dinitrophenol and stimulated by SH group reagents. The activation energy of binding was of the same order as the activation energy of an enzyme catalysed reaction. Uptake at 37° was rapidly inhibited although at 4° it was not. The INH binding mechanism had many of the properties of catalase and peroxidase. It seems likely that all these functions were part of one enzyme which was missing from INH-resistant BCG. Chromatographic studies on hot-water extracts of INH-treated BCG indicated that INH was converted into several unidentified products within the organism. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-47-3-389