Phosphate translocase

Burger, H. J., Maas, J., Hammerl, R., Schmidt, D., Strohschein, S., Hemmerle, H., Schubert, G., Petry, S., Kramer, W., Prolonged blood glucose reduction in mrp-2 deficient rats (GY/TR(—)) by the glucose-6-phosphate translocase inhibitor S 3025, Biochim. Biophys. Acta 2002,... 

Type lb Microsomal glucose 6-phosphate translocase Liver As in la also high susceptibility to bacterial infections... 

A second membrane transport system essential to oxidative phosphorylation is the phosphate translocase, which promotes symport of one H2PO4 and one H+ into the matrix. This transport process, too, is favored by the transmembrane proton gradient (Fig. 19-26). Notice that the process requires movement of one proton from the P to the N side of the inner membrane, consuming some of the energy of electron transfer. A complex of the ATP synthase and both translocases, the ATP synthasome, can be isolated from... 

Belkaid A, Copland IB, Massillon D, Annabi B. 2006. Silencing of the human microsomal glucose-6-phosphate translocase induces glioma cell death Potential new anticancer target for curcumin. FEBS Lett 580 3746-3752. 

Henunerle H, Burger HJ, Below P, Schubert G, Rippel R, Schindler PW, Paulus E, Herling AW. Chlorogenic acid and syn- 41. thetic chlorogenic acid derivatives novel inhibitors of hepatic glucose-6-phosphate translocase. J. Med. Chem. 1997 40 137-145. 

Gerin I, Veiga-da-Cunha M, Achouri Y, Collet IF, Van Schaftingen E. Sequence of a putative glucose 6-phosphate translocase, mutated in glycogen storage disease type lb. FEBS Lett. 1997 419 235-238. 

The transport of H2P02 across the inner mitochondrial membrane by the phosphate translocase is driven by the proton gradient. For every 4 protons that are transported out of the matrix, 3 drive the ATP synthase rotor and 1 drives the inward transport of phosphate. The simultaneous exchange of ADP3 and ATP4 , required for continuing ATP synthesis and mediated by the ADP-ATP translocator, is driven by the potential difference across the inner membrane. 

A second membrane transport system essential to oxidative phosphorylation is the phosphate translocase, which promotes symport of one H2POT and one into the matrix. This transport process, too, is favored by the transmembrane proton gradient (Fig. 

The other substrate for ATP synthase—inorganic phosphate— can come in by either of two modes in response to either component of the gradient. The phosphate translocase can operate in an antiport mode, transferring hydroxide ion (OH ) out of the matrix in response to the pH component of the gradient ... 

In this case, there is no net charge flow and the reaction is favored by the fact that the matrix is more basic than the intermembrane space. Alternatively, the phosphate translocase can operate in a sym-port mode ... 

Fig. 15.3. Pathways of glycogen metabolism. 15.16, Glycogen synthetase (liver) 15.11, brancher enzyme 15.13, phosphorylase (liver) 15.15, phosphorylase kinase (liver) 15.12, phosphorylase (muscle) 15.10, debrancher enzyme (liver + muscle) 15.8, glu-cose-6-phosphatase (liver) 15.8a, glucose-6-phosphate translocase 15.5, fructose-1,6-di-phosphatase 15.9, a-glucosidase UDPGlc, uridine diphosphate glucose Glc-l-P, glucose-1-phosphate Glc-6-P, glucose-6-phosphate F-6-P, fructose-6-phosphate F-l,6-DiP, fructose- 1,6-diphosphate...

Enzyme diagnosis GSD, other than gliicose-6-phosphate translocase Liver muscle Quick frozen -70 "C... 

Glucose-6-phosphate translocase Liver Assay unfrozen None... 

---