It is coded by the G6PD gene (1461 nucleotides)<ref>Gene ID: 29577449</ref>.
It is coded by the G6PD gene (1461 nucleotides)<ref>ID: 29577449</ref>.
== Catalytic activity ==
== Catalytic activity ==
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The Glucose-6-Phosphate Dehydrogenase is involved in the processing of carbohydrates as it has important roles in the glucose metabolic process (glycolysis and pentose phosphate pathway).
It also has a role in protecting cells from destruction as it produces the co-factor NADPH which plays a role in protecting cells from reactive oxygen species [1].
Genomic context
It is coded by the G6PD gene (1461 nucleotides)[2].
Catalytic activity
D-glucose 6-phosphate + NAD+ → 6-phospho-D-glucono-1,5-lactone + H+ + NADH[3]
KM=114 µM for G6PD (with NADP), KM=69 µM for G6PD (with NAD),
KM=8.0 µM for NADP, KM=160 µM for NAD.
Its regulation depends on the concentration of substrate and coenzyme, rate limiting step in pentose phosphate pathway[4].
Optimal activity conditions
Optimum pH is 5.4 - 8.9.
Evolutionary conservation
The different structures conserved evolutionary can be observed according to the scale following.
Mutagenesis inducing catalytic activity loss: +200 mutations have been identified. A change of amino acids leads to disruption of the normal
structure/function/reduce the expression of enzymes.
Structural highlights
It is formed of a homodimer, so a dimer of two identical monomers[5]. Each monomer is composed of 2 domains, 1 red and 1 green.
Depending on several conditions, it can dimerize to form tetramers. Each monomer in the complex has a substrate binding site that binds to G6P, and a catalytic coenzyme binding site that binds to NADP+/NADPH using the Rossman fold.
↑Ravera S, Calzia D, Morelli A, Panfoli I. Oligomerization studies of Leuconostoc mesenteroides G6PD activity after SDS-PAGE and blotting. Mol Biol (Mosk). 2010 May-Jun;44(3):472-6. PMID:20608171
↑Cosgrove MS, Naylor C, Paludan S, Adams MJ, Levy HR. On the mechanism of the reaction catalyzed by glucose 6-phosphate dehydrogenase. Biochemistry. 1998 Mar 3;37(9):2759-67. PMID:9485426 doi:10.1021/bi972069y
↑Cosgrove MS, Loh SN, Ha JH, Levy HR. The catalytic mechanism of glucose 6-phosphate dehydrogenases: assignment and 1H NMR spectroscopy pH titration of the catalytic histidine residue in the 109 kDa Leuconostoc mesenteroides enzyme. Biochemistry. 2002 Jun 4;41(22):6939-45. doi: 10.1021/bi0255219. PMID:12033926 doi:https://dx.doi.org/10.1021/bi0255219
↑Rowland P, Basak AK, Gover S, Levy HR, Adams MJ. The three-dimensional structure of glucose 6-phosphate dehydrogenase from Leuconostoc mesenteroides refined at 2.0 A resolution. Structure. 1994 Nov 15;2(11):1073-87. PMID:7881907
