Resolution and characterization of the glycine-cleavage reaction in pea leaf mitochondria. Properties of the forward reaction catalysed by glycine decarboxylase and serine hydroxymethyltransferase.
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Bourguignon J, Neuburger M, Douce R
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.
- PubMed ID
- 3143355 [ View in PubMed]
- Abstract
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.
DrugBank Data that Cites this Article
- Drug Targets
Drug Target Kind Organism Pharmacological Action Actions Pyridoxal phosphate Serine hydroxymethyltransferase, cytosolic Protein Humans UnknownCofactorDetails Pyridoxal phosphate Serine hydroxymethyltransferase, mitochondrial Protein Humans UnknownCofactorDetails