Resolution and characterization of the glycine-cleavage reaction in pea leaf mitochondria. Properties of the forward reaction catalysed by glycine decarboxylase and serine hydroxymethyltransferase

Biochem J. 1988 Oct 1;255(1):169-78. doi: 10.1042/bj2550169.


High-molecular-mass proteins from pea (Pisum sativum) mitochondrial matrix retained on an XM-300 Diaflo membrane ('matrix extract') exhibited high rates of glycine oxidation in the presence of NAD+ and tetrahydropteroyl-L-glutamic acid (H4 folate) as long as the medium exhibited a low ionic strength. Serine hydroxymethyltransferase (SHMT) (4 x 53 kDa) and the four proteins of the glycine-cleavage system, including a pyridoxal phosphate-containing enzyme ('P-protein'; 2 x 97 kDa), a carrier protein containing covalently bound lipoic acid ('H-protein'; 15.5 kDa), a protein exhibiting lipoamide dehydrogenase activity ('L-protein'; 2 x 61 kDa) and an H4 folate-dependent enzyme ('T-protein'; 45 kDa) have been purified to apparent homogeneity from the matrix extract by using gel filtration, ion-exchange and phenyl-Superose fast protein liquid chromatography. Gel filtration on Sephacryl S-300 in the presence of 50 mM-KCl proved to be the key step in disrupting this complex. During the course of glycine oxidation catalysed by the matrix extract a steady-state equilibrium in the production and utilization of 5,10-methylene-H4 folate was reached, suggesting that glycine cleavage and SHMT are linked together via a soluble pool of H4 folate. The rate of glycine oxidation catalysed by the matrix extract was sensitive to the NADH/NAD+ molar ratios, because NADH competitively inhibited the reaction catalysed by lipoamide dehydrogenase.

MeSH terms

  • Amino Acid Oxidoreductases / metabolism
  • Aminomethyltransferase
  • Carrier Proteins / metabolism
  • Chromatography, Gel
  • Electrophoresis, Polyacrylamide Gel
  • Glycine / metabolism*
  • Glycine Decarboxylase Complex H-Protein
  • Glycine Dehydrogenase (Decarboxylating)
  • Glycine Hydroxymethyltransferase / metabolism
  • Hydroxymethyl and Formyl Transferases*
  • Mitochondria / metabolism
  • Multienzyme Complexes / metabolism
  • NAD / metabolism
  • Oxidation-Reduction
  • Plant Proteins / metabolism
  • Plants / metabolism*
  • Pyruvate Dehydrogenase Complex / metabolism
  • Tetrahydrofolates / biosynthesis
  • Tetrahydrofolates / pharmacology
  • Thioctic Acid / analogs & derivatives
  • Thioctic Acid / metabolism
  • Transferases / metabolism


  • Carrier Proteins
  • Glycine Decarboxylase Complex H-Protein
  • Multienzyme Complexes
  • Plant Proteins
  • Pyruvate Dehydrogenase Complex
  • Tetrahydrofolates
  • glycine cleavage system
  • 5,10-methylenetetrahydrofolic acid
  • NAD
  • 5,6,7,8-tetrahydrofolic acid
  • Thioctic Acid
  • dihydrolipoic acid
  • Amino Acid Oxidoreductases
  • Glycine Dehydrogenase (Decarboxylating)
  • Transferases
  • Hydroxymethyl and Formyl Transferases
  • Glycine Hydroxymethyltransferase
  • Aminomethyltransferase
  • Glycine