Enzymic analysis of NADPH metabolism in β-lactam-producing Penicillium chrysogenum

Presence of a mitochondrial NADPH dehydrogenase

Journal article (2006)

Authors

DM Harris BT/Industriele Microbiologie - AS
J.A. Diderich BT/Industriele Microbiologie - AS
Z.A. van der Krogt BT/Industriele Microbiologie - AS
M.A.H. Luttik BT/Industriele Microbiologie - AS
W.M. van Gulik OLD BT/Cell Systems Engineering
JP van Dijken Bird Engineering B.V., BT/Industriele Microbiologie - AS
J.T. Pronk BT/Industriele Microbiologie - AS
Research Group
BT/Industriele Microbiologie (AS) (TU Delft)
Penicillium chrysogenum Metabolic engineering Mitochondria NADPH Redox metabolism Chemostat cultures Penicillin-G Respiratory chain
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Published Date

2006

Language

English

Reuse Rights

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Faculty

Applied Sciences

Department

BT/Biotechnologie

Research Group

BT/Industriele Microbiologie

Abstract

Based on assumed reaction network structures, NADPH availability has been proposed to be a key constraint in β-lactam production by Penicillium chrysogenum. In this study, NADPH metabolism was investigated in glucose-limited chemostat cultures of an industrial P. chrysogenum strain. Enzyme assays confirmed the NADP+-specificity of the dehydrogenases of the pentose-phosphate pathway and the presence of NADP+-dependent isocitrate dehydrogenase. Pyruvate decarboxylase/NADP+-linked acetaldehyde dehydrogenase and NADP+-linked glyceraldehyde-3- phosphate dehydrogenase were not detected. Although the NADPH requirement of penicillin-G-producing chemostat cultures was calculated to be 1.4-1.6-fold higher than that of non-producing cultures, in vitro measured activities of the major NADPH-providing enzymes were the same. Isolated mitochondria showed high rates of antimycin A-sensitive respiration of NADPH, thus indicating the presence of a mitochondrial NADPH dehydrogenase that oxidises cytosolic NADPH. The presence of this enzyme in P. chrysogenum might have important implications for stoichiometric modelling of central carbon metabolism and β-lactam production and may provide an interesting target for metabolic engineering.