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Mechanism of action of the pyruvate dehydrogenase multienzyme complex from Escherichia coli.

Publication ,  Journal Article
Angelides, KJ; Hammes, GG
Published in: Proc Natl Acad Sci U S A
October 1978

The extent of cooperativity among the polypeptide chain components in the overall reaction catalyzed by the pyruvate dehydrogenase multienzyme complex from Escherichia coli has been studied. Selective inactivation of the pyruvate dehydrogenase component with thiamin thiazolone pyrophosphate demonstrates that no cooperativity between this component and the overall catalytic reaction occurs: the amount of overall complex activity is directly proportional to the fraction of active pyruvate dehydrogenase component. The transacetylase component has two lipoic acid residues on each of its polypeptide chains that can be modified by N-[(3)H]ethylmaleimide in the presence of pyruvate and thiamin pyrophosphate. The kinetics of the loss of overall complex activity due to modification of the lipoyl residues on the transacetylase component by maleimide reagents shows that not all lipoic acids are coupled into the overall catalytic reaction and that acyl-group and electron pair transfer involving two or more lipoic acids per catalytic cycle must occur. Finally, full complex activity is found when only half the normal flavin content is present. The results indicate that extensive communication among lipoic acids in acyl-group and electron pair transfer must exist in the normal catalytic mechanism. These results are consistent with the average distances between catalytic sites measured by energy transfer experiments.

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Published In

Proc Natl Acad Sci U S A

DOI

ISSN

0027-8424

Publication Date

October 1978

Volume

75

Issue

10

Start / End Page

4877 / 4880

Location

United States

Related Subject Headings

  • Thiazoles
  • Thiamine Pyrophosphate
  • Pyruvate Dehydrogenase Complex
  • Flavin-Adenine Dinucleotide
  • Ethylmaleimide
  • Escherichia coli
 

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Angelides, K. J., & Hammes, G. G. (1978). Mechanism of action of the pyruvate dehydrogenase multienzyme complex from Escherichia coli. Proc Natl Acad Sci U S A, 75(10), 4877–4880. https://doi.org/10.1073/pnas.75.10.4877
Angelides, K. J., and G. G. Hammes. “Mechanism of action of the pyruvate dehydrogenase multienzyme complex from Escherichia coli.Proc Natl Acad Sci U S A 75, no. 10 (October 1978): 4877–80. https://doi.org/10.1073/pnas.75.10.4877.
Angelides KJ, Hammes GG. Mechanism of action of the pyruvate dehydrogenase multienzyme complex from Escherichia coli. Proc Natl Acad Sci U S A. 1978 Oct;75(10):4877–80.
Angelides, K. J., and G. G. Hammes. “Mechanism of action of the pyruvate dehydrogenase multienzyme complex from Escherichia coli.Proc Natl Acad Sci U S A, vol. 75, no. 10, Oct. 1978, pp. 4877–80. Pubmed, doi:10.1073/pnas.75.10.4877.
Angelides KJ, Hammes GG. Mechanism of action of the pyruvate dehydrogenase multienzyme complex from Escherichia coli. Proc Natl Acad Sci U S A. 1978 Oct;75(10):4877–4880.
Journal cover image

Published In

Proc Natl Acad Sci U S A

DOI

ISSN

0027-8424

Publication Date

October 1978

Volume

75

Issue

10

Start / End Page

4877 / 4880

Location

United States

Related Subject Headings

  • Thiazoles
  • Thiamine Pyrophosphate
  • Pyruvate Dehydrogenase Complex
  • Flavin-Adenine Dinucleotide
  • Ethylmaleimide
  • Escherichia coli