Journal article
Metabolic control analysis of the penicillin biosynthetic pathway: The influence of the LLD-ACV:bisACV ratio on the flux control
An extended kinetic model for the first two steps of the penicillin biosynthetic pathway in Penicillium chrysogenum is set up. It includes the formation and reduction of the dimer bis-delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine (bisACV) from the first pathway intermediate LLD-ACV and their parallel inhibition of the enzyme ACV synthetase (ACVS).
The kinetic model is based on Michaelis-Menten type kinetics, with non-competitive inhibition of the ACVS by both LLD-ACV and bisACV, and competitive inhibition of the isopenicillin N synthetase (IPNS) by glutathione. The inhibition constant of LLD-ACV, KACV is determined to be 0.54 mm. With the kinetic model metabolic control analysis is performed to identify the distribution of rate-control in the pathway at all ratios of LLD-ACV:bisACV.
It is concluded that the flux control totally resides at the IPNS. This is a result of the regulation of the ACVS by both the LLD-ACV and bisACV demanding a higher flux through the IPNS enzyme to alleviate their inhibition. The measurement of an intracellular ratio of LLD-ACV:bisACV to be in the range of 1-2 moles per moles emphasises the importance of a fast conversion of LLD-ACV to IPN, and accumulation of LLD-ACV above the K(m)-value of the IPNS should therefore be avoided.
Language: | English |
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Publisher: | Kluwer Academic Publishers |
Year: | 1999 |
Pages: | 145-154 |
Journal subtitle: | International Journal of General and Molecular Microbiology |
ISSN: | 15729699 and 00036072 |
Types: | Journal article |
DOI: | 10.1023/a:1001781808150 |
5-(2-aminoadipyl)cysteinylvaline ACV ACVS Acyltransferases Chromatography, High Pressure Liquid Glutathione IPNS Life Sciences Medical Microbiology Microbiology Models, Biological Oligopeptides Oxidoreductases Penicillin-Binding Proteins Penicillins Penicillium chrysogenum Peptide Synthases Plant Sciences Soil Science & Conservation acyl-CoA-6-aminopenicillanic acid acyltransferase alpha-aminoadipyl-cysteinyl-valine synthetase bis(aminoadipyl)-cysteinyl-valine bisACV isopenicillin N synthetase metabolic control analysis penicillin