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Metabolism of l-Malate and d-Malate by a Species of Pseudomonas

D J Hopper1, P J Chapman, S Dagley

  • 1Department of Biochemistry, University of Minnesota, St. Paul, Minnesota 55101.

Journal of Bacteriology
|December 1, 1970
PubMed

Insights

Pseudomonas species degrade gentisic acid to d-malate and pyruvate. This study investigates the specific enzymes and pathways involved in malate metabolism in Pseudomonas.

Area of Science:

  • Microbial metabolism
  • Enzymology
  • Bacterial biochemistry

Background:

  • Pseudomonas species are known for their metabolic versatility.
  • Understanding microbial degradation pathways is crucial for environmental and biotechnological applications.
  • Gentisic acid degradation and malate metabolism in Pseudomonas are not fully elucidated.

Purpose of the Study:

  • To characterize the degradation of gentisic acid by Pseudomonas.
  • To identify and describe the enzymes involved in malate metabolism.
  • To investigate the regulation of malate-metabolizing enzymes.

Main Methods:

  • Enzymatic assays using cell extracts and particulate fractions.
  • Growth studies with different substrates (m-cresol, d-malate, succinate).
  • Enzyme induction studies with and without protein synthesis inhibition (chloramphenicol).

Main Results:

  • Pseudomonas degrades gentisic acid to d-malate and pyruvate without ring isomerization.
  • A particulate enzyme oxidizes l-malate but not d-malate, independent of NAD(P).
  • An NADP-dependent l-malic enzyme is present; an NAD-dependent d-malic enzyme is induced by exogenous d-malate.

Conclusions:

  • Pseudomonas utilizes a unique pathway for gentisic acid degradation.
  • Distinct enzymes and regulatory mechanisms govern l-malate and d-malate metabolism.
  • The findings provide insights into bacterial metabolic flexibility and enzyme regulation.

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