Peroxisomal localization of glucose-6-phosphate dehydrogenase and pyrophosphate-stimulated dihydroxyacetone-phosphate acyltransferase in mouse kidney

Patel, Bhartiben N.; Mackness, Michael I.; Connock, Martin

doi:10.1042/bj2440443

Cited by 19 publications

(13 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Results obtained in this work showed that the proportion of each G6PDH and 6PGDH activities in peroxisomes, cytosol and chloroplasts of pea leaves was about 10, 10 and 80 %, respectively (results not shown). The proportion of G6PDH in peroxisomes agrees with that reported for cellular fractions of mouse kidney, where 10 % of the total G6PDH activity was also found in peroxisomes [63].…”

Section: Discussionsupporting

confidence: 89%

“…The EM immunocytochemical results reported in this paper confirmed the localization of G6PDH in pea leaf peroxisomes. In animals, the peroxisomal localization of G6PDH in mouse kidney [63] and in rat liver [47] has been reported. However, to our knowledge, the EM immunocytochemical localization of G6PDH has not been carried out thus far for any organism.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

A dehydrogenase-mediated recycling system of NADPH in plant peroxisomes

Corpas

Barroso

Sandalio

et al. 1998

Biochemical Journal

153

115

View full text Add to dashboard Cite

The presence of the two NADP-dependent dehydrogenases of the pentose phosphate pathway has been investigated in plant peroxisomes from pea (Pisum sativum L.) leaves. Both enzymes, glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (6PGDH; EC 1.1.1.44), were present in the matrix of leaf peroxisomes, and their kinetic properties were studied. G6PDH and 6PGDH showed a typical Michaelis-Menten kinetic saturation curve, and had specific activities of 12.4 and 29.6 mU/mg protein, respectively. The Km values of G6PDH and 6PGDH for glucose 6-phosphate and for 6-phosphogluconate were 107.3 and 10.2 microM, respectively. Dithiothreitol did not inhibit G6PDH activity. By isoelectric focusing of peroxisomal matrices, the G6PDH activity was resolved into three isoforms with isoelectric points of 5.55, 5.30 and 4.85. The isoelectric point of peroxisomal 6PGDH was 5.10. Immunoblot analyses of peroxisomal matrix with an antibody against yeast G6PDH revealed a single cross-reactive band of 56 kDa. Post-embedment, EM immunogold labelling of G6PDH confirmed that this enzyme was localized in the peroxisomal matrices, the thylakoid membrane and matrix of chloroplasts, and the cytosol. The presence of the two oxidative enzymes of the pentose phosphate pathway in plant peroxisomes implies that these organelles have the capacity to reduce NADP+ to NADPH for its re-utilization in the peroxisomal metabolism. NADPH is particularly required for the ascorbate-glutathione cycle, which has been recently demonstrated in plant peroxisomes [Jiménez, Hernández, del Río and Sevilla (1997) Plant Physiol. 114, 275-284] and represents an important antioxidant protection system against H2O2 generated in peroxisomes.

show abstract

Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

A dehydrogenase-mediated recycling system of NADPH in plant peroxisomes

Corpas

Barroso

Sandalio

et al. 1998

Biochemical Journal

153

115

View full text Add to dashboard Cite

show abstract

“…There are other enzymes besides IDH1 present in the cytosol of the cell that can form NADPH, such as malic enzyme 1 and glucose-6-phosphate dehydrogenase. Although glucose-6-phosphate dehydrogenase enzyme activity has been detected in peroxisomes [29, 30], its concentration in peroxisomes might be lower than that of IDH1. Its C-terminus sequence tripeptide (histidine-lysine-leucine) suggests that, compared to the C-terminus tripeptide sequence of the IDH1 protein (alanine-lysine-leucine), it would be a poor ligand for PEX5, a receptor that functions to import proteins into peroxisomes [31, 32].…”

Section: 0 Discussionmentioning

confidence: 99%

Knockdown of both mitochondrial isocitrate dehydrogenase enzymes in pancreatic beta cells inhibits insulin secretion

MacDonald

Brown

Longacre

et al. 2013

Biochimica et Biophysica Acta (BBA) - General Subjects

View full text Add to dashboard Cite

Background There are three isocitrate dehydrogenases (IDHs) in the pancreatic insulin cell; IDH1 (cytosolic) and IDH2 (mitochondrial) use NADP(H). IDH3 is mitochondrial, uses NAD(H) and was believed to be the IDH that supports the citric acid cycle. Methods With shRNAs targeting mRNAs for these enzymes we generated cell lines from INS-1 832/13 cells with severe (80%–90%) knockdown of the mitochondrial IDHs separately and together in the same cell line. Results With knockdown of both mitochondrial IDH’s mRNA, enzyme activity and protein level, but not with knockdown of one mitochondrial IDH, glucose- and BCH (an allosteric activator of glutamate dehydrogenase)-plus-glutamine-stimulated insulin release were inhibited. Cellular levels of citrate, α-ketoglutarate, malate and ATP were altered in patterns consistent with blockage at the mitochondrial IDH reactions. We were able to generate only 50% knockdown of Idh1 mRNA in multiple cell lines (without inhibition of insulin release) possibly because greater knockdown of IDH1 was not compatible with cell line survival. Conclusions The mitochondrial IDHs are redundant for insulin secretion. When both enzymes are severely knocked down, their low activities (possibly assisted by transport of IDH products and other metabolic intermediates from the cytosol into mitochondria) are sufficient for cell growth, but inadequate for insulin secretion when the requirement for intermediates is certainly more rapid. The results also indicate that IDH2 can support the citric acid cycle. General Significance As almost all mammalian cells possess substantial amounts of all three IDH enzymes, the biological principles suggested by these results are probably extrapolatable to many tissues.

show abstract

“…This indicates that the microsomal fraction contains a DHAPAT enzyme different from the peroxisomal enzyme, and that the mitochondrial enzyme activity may derive from peroxisomal fragments. This view is shared by Patel et al (1987) andSkorve et al (1990). Jones & Hajra (1977) found that in guinea-pig liver the DHAPAT activity is present only in peroxisomes, in contrast with rat liver, where it is present also in microsomes.…”

Section: Discussionmentioning

confidence: 94%

Studies of dihydroxyacetone phosphate acyltransferase in rat small intestine. Subcellular localization and effect of partially hydrogenated fish oil and clofibrate

Ruyter

Lund

Thomassen

et al. 1992

Biochemical Journal

View full text Add to dashboard Cite

The subcellular localization of dihydroxyacetone phosphate acyltransferase (DHAPAT) activity in rat small intestine was investigated by Nycodenz-gradient centrifugation. We found that DHAPAT had a predominant peroxisomal distribution, with a separate enzyme activity located in the microsomal fraction, the same distribution as found in rat liver. The effect of feeding rats on a diet with 20% (w/w) partially hydrogenated fish oil (PHFO) or 0.3% clofibrate on the activity of DHAPAT in rat small intestine and liver was studied. Both 20% PHFO and 0.3% clofibrate gave a 1.8-fold stimulation of the specific activities of DHAPAT in peroxisomes of the small intestine, whereas in the liver 20% PHFO gave a 1.4-fold stimulation and 0.3% clofibrate a 1.6-fold stimulation of the total DHAPAT activities in the postnuclear supernatant. The specific activities of DHAPAT in liver were not affected.

show abstract

Peroxisomal localization of glucose-6-phosphate dehydrogenase and pyrophosphate-stimulated dihydroxyacetone-phosphate acyltransferase in mouse kidney

Cited by 19 publications

References 18 publications

A dehydrogenase-mediated recycling system of NADPH in plant peroxisomes

A dehydrogenase-mediated recycling system of NADPH in plant peroxisomes

Knockdown of both mitochondrial isocitrate dehydrogenase enzymes in pancreatic beta cells inhibits insulin secretion

Studies of dihydroxyacetone phosphate acyltransferase in rat small intestine. Subcellular localization and effect of partially hydrogenated fish oil and clofibrate

Contact Info

Product

Resources

About