Kinetic analysis of cephalosporin biosynthesis in <i>Streptomyces clavuligerus</i>

Malmberg, Li Hong; Hu, Wei‐Shou

doi:10.1002/bit.260380815

Cited by 33 publications

(1 citation statement)

References 19 publications

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“…The genes responsible for cephamycin C biosynthesis are clustered (8) and include resistance, transport, regulatory, and biosynthetic structural components. Lysine‐ϵ‐aminotransferase (LAT) is an early and rate‐limiting enzyme for cephamycin C biosynthesis (9−11). Kinetic studies of LAT activity in S .…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Analysis of Spatio-Temporal Gene Expression for Cephamycin Biosynthesis in Streptomyces clavuligerus

Kyung

Sherman

2001

Biotechnol. Prog.

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Linkage between structural and regulatory genes implies that a direct correlation should exist between the spatio-temporal distribution of their expression. Green fluorescent protein (GFP) and cyan fluorescent protein (CFP) were used as reporters to analyze simultaneously expression of lysine-epsilon-aminotransferase (LAT) and its corresponding genetic regulator, CcaR. The isogenic strain containing lat::gfp and ccaR::cfp in the chromosome produced cephamycin C at levels similar to wild type Streptomyces clavuligerus. Confocal laser scanning microscopy revealed that expression of both LAT and CcaR in liquid culture was temporally dynamic and spatially heterogeneous in S. clavuligerus mycelia. During the early culture stage only a part of the mycelia began to express LAT and CcaR at low levels. As the culture aged, expression levels and the population of mycelia expressing LAT and CcaR increased and were followed late in the growth cycle by a reduction of the mycelia population expressing LAT and CcaR. The approach provides a precise simultaneous temporal-spatial expression profile and corroborates the regulatory linkage between ccaR and lat in S. clavuligerus.

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Section: Introductionmentioning

confidence: 99%

Simultaneous Analysis of Spatio-Temporal Gene Expression for Cephamycin Biosynthesis in Streptomyces clavuligerus

Kyung

Sherman

2001

Biotechnol. Prog.

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Pathway kinetics and metabolic control analysis of a high-yielding strain ofPenicillium chrysogenum during fed batch cultivations

Pissara

Nielsen

Bazin

1996

Biotechnol. Bioeng.

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A kinetic model representing the pathway for the biosynthesis of penicillin by P. chrysogenum has been developed. The model is capable of describing the flux through the biosynthetic pathway, and model simulations correspond well with measurements of intermediates and end products. One feature of the present model structure is that it assumes the kinetics of the enzyme isopenicillin N synthetase (IPNS) to be first order with respect to the dissolved oxygen concentration in the range of 0.070 to 0.18 mM (25% to 70% saturation with air). Thus, it indicates the importance that molecular oxygen has on the rate of the reaction catalyzed by this enzyme, and consequently as an enhancer of the specific rate of penicillin production. Using the kinetic model, metabolic control analysis (MCA) of the pathway was performed. The determined flux control coefficients suggested that, during the production phase, the flux is controlled by IPNS as this enzyme becomes saturated with tripeptide δ‐(L‐α‐amino‐adipyl)‐L‐cysteinyl‐D‐valine (LLD‐ACV). In the simulations, oxygen was shown to be a bottleneck alleviator by stimulating the rate of IPNS which prevents the accumulation of LLD‐ACV. As a consequence of this stimulation, the rate‐controlling step was moved to another place in the pathway. © 1996 John Wiley & Sons, Inc.

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Metabolic modeling of polyhydroxybutyrate biosynthesis

Leaf

Srienc

1998

Biotechnol. Bioeng.

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A mathematical model describing intracellular polyhydroxybutyrate (PHB) synthesis in Alcaligenes eutrophus has been constructed. The model allows investigation of issues such as the existence of rate‐limiting enzymatic steps, possible regulatory mechanisms in PHB synthesis, and the effects different types of rate expressions have on model behavior. Simulations with the model indicate that activities of all PHB pathway enzymes influence overall PHB flux and that no single enzymatic step can easily be identified as rate limiting. Simulations also support regulatory roles for both thiolase and reductase, mediated through AcCoA/CoASH and NADPH/NADP+ ratios, respectively. To make the model more realistic, complex rate expressions for enzyme‐catalyzed reactions were used which reflect both the reversibility of the reactions and the reaction mechanisms. Use of the complex kinetic expressions dramatically changed the behavior of the system compared to a simple model containing only Michaelis–Menten kinetic expressions; the more complicated model displayed different responses to changes in enzyme activities as well as inhibition of flux by the reaction products CoASH and NADP+. These effects can be attributed to reversible rate expressions, which allow prediction of reaction rates under conditions both near and far from equilibrium. ©1998 John Wiley & Sons, Inc. Biotechnol Bioeng 57: 557‐570, 1998.

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Kinetic analysis of cephalosporin biosynthesis in Streptomyces clavuligerus

Cited by 33 publications

References 19 publications

Simultaneous Analysis of Spatio-Temporal Gene Expression for Cephamycin Biosynthesis in Streptomyces clavuligerus

Simultaneous Analysis of Spatio-Temporal Gene Expression for Cephamycin Biosynthesis in Streptomyces clavuligerus

Pathway kinetics and metabolic control analysis of a high-yielding strain ofPenicillium chrysogenum during fed batch cultivations

Metabolic modeling of polyhydroxybutyrate biosynthesis

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