Partial purification and characterization of the maize mitochondrial pyruvate dehydrogenase complex

Plant Physiology
J J ThelenDouglas D Randall

Abstract

The pyruvate dehydrogenase complex was partially purified and characterized from etiolated maize (Zea mays L.) shoot mitochondria. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed proteins of 40, 43, 52 to 53, and 62 to 63 kD. Immunoblot analyses identified these proteins as the E1beta-, E1alpha-, E2-, and E3-subunits, respectively. The molecular mass of maize E2 is considerably smaller than that of other plant E2 subunits (76 kD). The activity of the maize mitochondrial complex has a pH optimum of 7.5 and a divalent cation requirement best satisfied by Mg2+. Michaelis constants for the substrates were 47, 3, 77, and 1 &mgr;m for pyruvate, coenzyme A (CoA), NAD+, and thiamine pyrophosphate, respectively. The products NADH and acetyl-CoA were competitive inhibitors with respect to NAD+ and CoA, and the inhibition constants were 15 and 47 &mgr;m, respectively. The complex was inactivated by phosphorylation and was reactivated after the removal of ATP and the addition of Mg2+.

References

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Citations

Sep 2, 2003·Metabolic Engineering·Fernando CarrariAlisdair R Fernie
May 25, 2002·European Journal of Biochemistry·Alejandro Tovar-MendezDouglas D Randall
Jan 13, 2000·Biochemical and Biophysical Research Communications·B P MooneyD D Randall
Aug 19, 2009·Proteomics·Jun ItoJoshua L Heazlewood
Feb 14, 2008·The Plant Journal : for Cell and Molecular Biology·Jan A Miernyk, Jay J Thelen
Oct 3, 1998·The Journal of Biological Chemistry·J J ThelenD D Randall
Sep 12, 2002·Annual Review of Plant Biology·Brian P MooneyDouglas D Randall
Apr 12, 2020·Mitochondrion·Abir U Igamberdiev

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