Glycerol-3-phosphate dehydrogenase#GPD2

GPDH plays a major role in lipid biosynthesis. Through the reduction of dihydroxyacetone phosphate into glycerol 3-phosphate, GPDH allows the prompt dephosphorylation of glycerol 3-phosphate into glycerol.{{cite journal | vauthors = Harding JW, Pyeritz EA, Copeland ES, White HB | title = Role of glycerol 3-phosphate dehydrogenase in glyceride metabolism. Effect of diet on enzyme activities in chicken liver | journal = The Biochemical Journal | volume = 146 | issue = 1 | pages = 223–9 | date = Jan 1975 | pmid = 167714 | pmc = 1165291 | doi=10.1042/bj1460223}} Additionally, GPDH is one of the enzymes involved in maintaining the redox potential across the inner mitochondrial membrane.

File:Schematic overview of fermentative and oxidative glucose metabolism of Saccharomyc.png. (A) upper part of glycolysis, which includes two sugar phosphorylation reactions. (B) fructose-1,6-bisphosphate aldolase, splitting the C6-molecule into two triose phosphates (C) triosephosphate isomerase, interconverting DHAP and GAP. (D) glycerol pathway reducing DHAP to glycerol-3-phosphate (G3P) by G3P dehydrogenase, followed by dephosphorylation to glycerol by G3Pase. (E) The lower part of glycolysis converts GAP to pyruvate while generating 1 NADH and 2 ATP via a series of 5 enzymes. (F) Alcoholic fermentation; decarboxylation of pyruvate by pyruvate decarboxylase, followed by reduction of acetaldehyde to ethanol. (G) mitochondrial pyruvate-dehydrogenase converts pyruvate to acetyl-CoA, which enters the tricarboxylic acid cycle. (H) external mitochondrial NADH dehydrogenases. (I) mitochondrial G3P dehydrogenase. Electrons of these three dehydrogenases enter the respiratory chain at the level of the quinol pool (Q). (J) internal mitochondrial NADH dehydrogenase. (K) ATP synthase. (L) generalized scheme of NADH shuttle. (M) formate oxidation by formate dehydrogenase.{{cite journal | vauthors = Geertman JM, van Maris AJ, van Dijken JP, Pronk JT | title = Physiological and genetic engineering of cytosolic redox metabolism in Saccharomyces cerevisiae for improved glycerol production | journal = Metabolic Engineering | volume = 8 | issue = 6 | pages = 532–42 | date = Nov 2006 | pmid = 16891140 | doi = 10.1016/j.ymben.2006.06.004 }}]]

The NAD+/NADH coenzyme couple act as an electron reservoir for metabolic redox reactions, carrying electrons from one reaction to another.{{cite journal | vauthors = Ansell R, Granath K, Hohmann S, Thevelein JM, Adler L | title = The two isoenzymes for yeast NAD+-dependent glycerol 3-phosphate dehydrogenase encoded by GPD1 and GPD2 have distinct roles in osmoadaptation and redox regulation | journal = The EMBO Journal | volume = 16 | issue = 9 | pages = 2179–87 | date = May 1997 | pmid = 9171333 | pmc = 1169820 | doi = 10.1093/emboj/16.9.2179 }} Most of these metabolism reactions occur in the mitochondria. To regenerate NAD+ for further use, NADH pools in the cytosol must be reoxidized. Since the mitochondrial inner membrane is impermeable to both NADH and NAD+, these cannot be freely exchanged between the cytosol and mitochondrial matrix.

One way to shuttle this reducing equivalent across the membrane is through the Glycerol-3-phosphate shuttle, which employs the two forms of GPDH:

• Cytosolic GPDH, or GPD1, is localized to the outer membrane of the mitochondria facing the cytosol, and catalyzes the reduction of dihydroxyacetone phosphate into glycerol-3-phosphate.
• In conjunction, Mitochondrial GPDH, or GPD2, is embedded on the outer surface of the inner mitochondrial membrane, overlooking the cytosol, and catalyzes the oxidation of glycerol-3-phosphate to dihydroxyacetone phosphate.{{cite journal | vauthors = Kota V, Rai P, Weitzel JM, Middendorff R, Bhande SS, Shivaji S | title = Role of glycerol-3-phosphate dehydrogenase 2 in mouse sperm capacitation | journal = Molecular Reproduction and Development | volume = 77 | issue = 9 | pages = 773–83 | date = Sep 2010 | pmid = 20602492 | doi = 10.1002/mrd.21218 | s2cid = 19691537 }}

The reactions catalyzed by cytosolic (soluble) and mitochondrial GPDH are as follows:

There are two forms of GPDH:

The following human genes encode proteins with GPDH enzymatic activity:

Cytosolic Glycerol-3-phosphate dehydrogenase (GPD1), is an NAD+-dependent enzyme{{cite journal | vauthors = Guindalini C, Lee KS, Andersen ML, Santos-Silva R, Bittencourt LR, Tufik S | title = The influence of obstructive sleep apnea on the expression of glycerol-3-phosphate dehydrogenase 1 gene | journal = Experimental Biology and Medicine | volume = 235 | issue = 1 | pages = 52–6 | date = Jan 2010 | pmid = 20404019 | doi = 10.1258/ebm.2009.009150 | s2cid = 207194967 | url = http://ebm.rsmjournals.com/cgi/content/full/235/1/52 | access-date = 2011-05-16 | archive-url = https://web.archive.org/web/20110724152256/http://ebm.rsmjournals.com/cgi/content/full/235/1/52 | archive-date = 2011-07-24 | url-status = dead | url-access = subscription }} that reduces dihydroxyacetone phosphate to glycerol-3-phosphate. Simultaneously, NADH is oxidized to NAD+ in the following reaction:

File:GPD1 Reaction Mechanism.png

As a result, NAD+ is regenerated for further metabolic activity.

GPD1 consists of two subunits,{{cite journal | vauthors = Bunoust O, Devin A, Avéret N, Camougrand N, Rigoulet M | title = Competition of electrons to enter the respiratory chain: a new regulatory mechanism of oxidative metabolism in Saccharomyces cerevisiae | journal = The Journal of Biological Chemistry | volume = 280 | issue = 5 | pages = 3407–13 | date = Feb 2005 | pmid = 15557339 | doi = 10.1074/jbc.M407746200 | doi-access = free }} and reacts with dihydroxyacetone phosphate and NAD+ though the following interaction:

Figure 4. The putative active site. The phosphate group of DHAP is half-encircled by the side-chain of Arg269, and interacts with Arg269 and Gly268 directly by hydrogen bonds (not shown). The conserved residues Lys204, Asn205, Asp260 and Thr264 form a stable hydrogen bonding network. The other hydrogen bonding network includes residues Lys120 and Asp260, as well as an ordered water molecule (with a B-factor of 16.4 Å2), which hydrogen bonds to Gly149 and Asn151 (not shown). In these two electrostatic networks, only the ε-NH₃⁺ group of Lys204 is the nearest to the C2 atom of DHAP (3.4 Å).

Mitochondrial glycerol-3-phosphate dehydrogenase (GPD2), catalyzes the irreversible oxidation of glycerol-3-phosphate to dihydroxyacetone phosphate and concomitantly transfers two electrons from FAD to the electron transport chain. GPD2 consists of 4 identical subunits.{{cite journal | vauthors = Kota V, Dhople VM, Shivaji S | title = Tyrosine phosphoproteome of hamster spermatozoa: role of glycerol-3-phosphate dehydrogenase 2 in sperm capacitation | journal = Proteomics | volume = 9 | issue = 7 | pages = 1809–26 | date = Apr 2009 | pmid = 19333995 | doi = 10.1002/pmic.200800519 | s2cid = 9248320 }}

File:GPD2 Reaction Mechanism.png

• Studies indicate that GPDH is mostly unaffected by pH changes: neither GPD1 or GPD2 is favored under certain pH conditions.
• At high salt concentrations (E.g. NaCl), GPD1 activity is enhanced over GPD2, since an increase in the salinity of the medium leads to an accumulation of glycerol in response.
• Changes in temperature do not appear to favor neither GPD1 nor GPD2.{{cite journal | vauthors = Kumar S, Kalyanasundaram GT, Gummadi SN | title = Differential response of the catalase, superoxide dismutase and glycerol-3-phosphate dehydrogenase to different environmental stresses in Debaryomyces nepalensis NCYC 3413 | journal = Current Microbiology | volume = 62 | issue = 2 | pages = 382–7 | date = Feb 2011 | pmid = 20644932 | doi = 10.1007/s00284-010-9717-z | s2cid = 41613712 }}

{{main|Glycerol phosphate shuttle}}

The cytosolic together with the mitochondrial glycerol-3-phosphate dehydrogenase work in concert. Oxidation of cytoplasmic NADH by the cytosolic form of the enzyme creates glycerol-3-phosphate from dihydroxyacetone phosphate. Once the glycerol-3-phosphate has moved through the outer mitochondrial membrane it can then be oxidised by a separate isoform of glycerol-3-phosphate dehydrogenase that uses quinone as an oxidant and FAD as a co-factor. As a result, there is a net loss in energy, comparable to one molecule of ATP.

The combined action of these enzymes maintains the NAD+/NADH ratio that allows for continuous operation of metabolism.

The fundamental role of GPDH in maintaining the NAD+/NADH potential, as well as its role in lipid metabolism, makes GPDH a factor in lipid imbalance diseases, such as obesity.

• Enhanced GPDH activity, particularly GPD2, leads to an increase in glycerol production. Since glycerol is a main subunit in lipid metabolism, its abundance can easily lead to an increase in triglyceride accumulation at a cellular level. As a result, there is a tendency to form adipose tissue leading to an accumulation of fat that favors obesity.{{cite journal | vauthors = Xu SP, Mao XY, Ren FZ, Che HL | title = Attenuating effect of casein glycomacropeptide on proliferation, differentiation, and lipid accumulation of in vitro Sprague-Dawley rat preadipocytes | journal = Journal of Dairy Science | volume = 94 | issue = 2 | pages = 676–83 | date = Feb 2011 | pmid = 21257036 | doi = 10.3168/jds.2010-3827 | doi-access = free }}
• GPDH has also been found to play a role in Brugada syndrome. Mutations in the gene encoding GPD1 have been proven to cause defects in the electron transport chain. This conflict with NAD+/NADH levels in the cell is believed to contribute to defects in cardiac sodium ion channel regulation and can lead to a lethal arrhythmia during infancy.{{cite journal | vauthors = Van Norstrand DW, Valdivia CR, Tester DJ, Ueda K, London B, Makielski JC, Ackerman MJ | title = Molecular and functional characterization of novel glycerol-3-phosphate dehydrogenase 1 like gene (GPD1-L) mutations in sudden infant death syndrome | journal = Circulation | volume = 116 | issue = 20 | pages = 2253–9 | date = Nov 2007 | pmid = 17967976 | pmc = 3332545 | doi = 10.1161/CIRCULATIONAHA.107.704627 }}

The mitochondrial isoform of G3P dehydrogenase is thought to be inhibited by metformin, a first line drug for type 2 diabetes.

{{cite journal | vauthors = Ferrannini E | title = The target of metformin in type 2 diabetes | journal = The New England Journal of Medicine | volume = 371 | issue = 16 | pages = 1547–8 | date = Oct 2014 | pmid = 25317875 | doi = 10.1056/NEJMcibr1409796 }}

Sarcophaga barbata was used to study the oxidation of L-3-glycerophosphate in mitochondria. It is found that the L-3-glycerophosphate does not enter the mitochondrial matrix, unlike pyruvate. This helps locate the L-3-glycerophosphate-flavoprotein oxidoreductase, which is on the inner membrane of the mitochondria.

Glycerol-3-phosphate dehydrogenase consists of two protein domains. The N-terminal domain is an NAD-binding domain, and the C-terminus acts as a substrate-binding domain.{{cite journal | vauthors = Suresh S, Turley S, Opperdoes FR, Michels PA, Hol WG | title = A potential target enzyme for trypanocidal drugs revealed by the crystal structure of NAD-dependent glycerol-3-phosphate dehydrogenase from Leishmania mexicana | journal = Structure | volume = 8 | issue = 5 | pages = 541–52 | date = May 2000 | pmid = 10801498 | doi = 10.1016/s0969-2126(00)00135-0 | doi-access = free }} However, dimer and tetramer interface residues are involved in GAPDH-RNA binding, as GAPDH can exhibit several moonlighting activities, including the modulation of RNA binding and/or stability.{{cite journal | vauthors = White MR, Khan MM, Deredge D, Ross CR, Quintyn R, Zucconi BE, Wysocki VH, Wintrode PL, Wilson GM, Garcin ED | title = A dimer interface mutation in glyceraldehyde-3-phosphate dehydrogenase regulates its binding to AU-rich RNA | language = en | journal = The Journal of Biological Chemistry | volume = 290 | issue = 3 | pages = 1770–85 | date = Jan 2015 | pmid = 25451934 | pmc = 4340419 | doi = 10.1074/jbc.M114.618165 | doi-access = free }}

• substrate pages: glycerol 3-phosphate, dihydroxyacetone phosphate
• related topics: glycerol phosphate shuttle, creatine kinase, glycolysis, gluconeogenesis

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• {{cite book | author = Baranowski T |veditors=Boyer PD, Lardy H, Myrbäck K | title = The Enzymes | edition = 2nd | year = 1963 | publisher = Academic Press | location = New York | pages = 85–96 | chapter = α-Glycerophosphate dehydrogenase }}
• {{cite journal | vauthors = Brosemer RW, Kuhn RW | title = Comparative structural properties of honeybee and rabbit alpha-glycerophosphate dehydrogenases | journal = Biochemistry | volume = 8 | issue = 5 | pages = 2095–105 | date = May 1969 | pmid = 4307630 | doi = 10.1021/bi00833a047 }}
• {{cite journal | vauthors = O'Brien SJ, MacIntyre RJ | title = The -glycerophosphate cycle in Drosophila melanogaster. I. Biochemical and developmental aspects | journal = Biochemical Genetics | volume = 7 | issue = 2 | pages = 141–61 | date = Oct 1972 | pmid = 4340553 | doi = 10.1007/BF00486085 | s2cid = 22009695 }}
• {{cite journal | vauthors = Warkentin DL, Fondy TP | title = Isolation and characterization of cytoplasmic L-glycerol-3-phosphate dehydrogenase from rabbit-renal-adipose tissue and its comparison with the skeletal-muscle enzyme | journal = European Journal of Biochemistry | volume = 36 | issue = 1 | pages = 97–109 | date = Jul 1973 | pmid = 4200180 | doi = 10.1111/j.1432-1033.1973.tb02889.x | doi-access = free }}
• {{cite journal | vauthors = Albertyn J, van Tonder A, Prior BA | title = Purification and characterization of glycerol-3-phosphate dehydrogenase of Saccharomyces cerevisiae | journal = FEBS Letters | volume = 308 | issue = 2 | pages = 130–2 | date = Aug 1992 | pmid = 1499720 | doi = 10.1016/0014-5793(92)81259-O | s2cid = 39643279 | doi-access = free }}
• {{cite journal | vauthors = Koekemoer TC, Litthauer D, Oelofsen W | title = Isolation and characterization of adipose tissue glycerol-3-phosphate dehydrogenase | journal = The International Journal of Biochemistry & Cell Biology | volume = 27 | issue = 6 | pages = 625–32 | date = Jun 1995 | pmid = 7671141 | doi = 10.1016/1357-2725(95)00012-E }}
• {{cite journal | vauthors = Påhlman IL, Larsson C, Averét N, Bunoust O, Boubekeur S, Gustafsson L, Rigoulet M | title = Kinetic regulation of the mitochondrial glycerol-3-phosphate dehydrogenase by the external NADH dehydrogenase in Saccharomyces cerevisiae | journal = The Journal of Biological Chemistry | volume = 277 | issue = 31 | pages = 27991–5 | date = Aug 2002 | pmid = 12032156 | doi = 10.1074/jbc.M204079200 | url = http://www.jbc.org/content/277/31/27991.full | doi-access = free | url-access = subscription }}
• {{cite journal | vauthors = Overkamp KM, Bakker BM, Kötter P, van Tuijl A, de Vries S, van Dijken JP, Pronk JT | title = In vivo analysis of the mechanisms for oxidation of cytosolic NADH by Saccharomyces cerevisiae mitochondria | journal = Journal of Bacteriology | volume = 182 | issue = 10 | pages = 2823–30 | date = May 2000 | pmid = 10781551 | pmc = 101991 | doi = 10.1128/JB.182.10.2823-2830.2000 | citeseerx = 10.1.1.335.5313 }}
• {{cite journal | vauthors = Dawson AG, Cooney GJ | title = Reconstruction of the alpha-glycerolphosphate shuttle using rat kidney mitochondria | journal = FEBS Letters | volume = 91 | issue = 2 | pages = 169–72 | date = Jul 1978 | pmid = 210038 | doi = 10.1016/0014-5793(78)81164-8 | doi-access = free }}
• {{cite journal | vauthors = Opperdoes FR, Borst P, Bakker S, Leene W | title = Localization of glycerol-3-phosphate oxidase in the mitochondrion and particulate NAD+-linked glycerol-3-phosphate dehydrogenase in the microbodies of the bloodstream form to Trypanosoma brucei | journal = European Journal of Biochemistry | volume = 76 | issue = 1 | pages = 29–39 | date = Jun 1977 | pmid = 142010 | doi = 10.1111/j.1432-1033.1977.tb11567.x | doi-access = free }}
• {{cite journal | vauthors = Eswaramoorthy S, Bonanno JB, Burley SK, Swaminathan S | title = Mechanism of action of a flavin-containing monooxygenase | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 103 | issue = 26 | pages = 9832–7 | date = Jun 2006 | pmid = 16777962 | pmc = 1502539 | doi = 10.1073/pnas.0602398103 | bibcode = 2006PNAS..103.9832E | doi-access = free }}

{{refend}}

• equivalent entries:
• {{MeshName|alphaGPDH}}
• [https://www.ncbi.nlm.nih.gov/sites/entrez?Db=mesh&Cmd=ShowDetailView&TermToSearch=68050536 GPDH]
• Yeast genome database GO term: [http://db.yeastgenome.org/cgi-bin/GO/goTerm.pl?goid=4367 GPDH] {{Webarchive|url=https://web.archive.org/web/20071224215040/http://db.yeastgenome.org/cgi-bin/GO/goTerm.pl?goid=4367 |date=2007-12-24 }}

{{InterPro content|IPR011128}}

{{InterPro content|IPR006109}}

{{Alcohol oxidoreductases}}

{{Enzymes}}

{{Portal bar|Biology|border=no}}

{{DEFAULTSORT:Glycerol-3-Phosphate Dehydrogenase}}

Category:Protein domains

Category:EC 1.1.1