(±)8-Amino-7-Oxononanoic acid ((±)8-KAPA) is a racemic mixture of 8(R)-KAPA and the vitamer of biotin 8(S)-KAPA .[1],[2] It is biosynthesized as the 8(S) form but racemizes in culture media in a pH-dependent manner, with a higher racemization rate under very low (pH <2), physiological, and basic pH conditions.[2] 8(S)-KAPA increases proliferation in S. cerevisiae in a concentration-dependent manner and is an intermediate in the biosynthesis of biotin in microbes. 8(S)-KAPA, but not 8(R)-KAPA, is a substrate for E. coli and M. tuberculosis 7,8-diaminopelargonic acid aminotransferase (DAPA AT), which leads to accumulation of 8(R)-KAPA in M. tuberculosis cultures after exogenous application of racemic KAPA.
References:
[1].Lucet, D., Le Gall, T., Mioskowski, C., et al.First synthesis of both enantiomers of the biotin vitamer 8-amino-7-oxopelargonic acidTetrahedron-Asymmetr.7(4)985-988(1996).
[2].Mann, S., Colliandre, L., Labesse, G., et al.Inhibition of 7,8-diaminopelargonic acid aminotransferase from Mycobacterium tuberculosis by chiral and achiral anologs of its substrate: biological implicationsBiochimie91(7)826-834(2009).