The purification and kinetic properties of biophosphoglycerate synthase from horse red blood cells. |
| |
Authors: | A B Rose S Dube |
| |
Institution: | The Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 USA |
| |
Abstract: | Bisphosphoglycerate synthase from horse red cells has been purified to apparent homogeneity by a simple and efficient new procedure incorporating chromatography on a column of Sepharose 4B derivatized with blue dextran. The enzyme is similar to the human red cell synthase in subunit size. It is phosphorylated by either glycerate-1,3-P2 or glycerate-2,3-P2 to form a phosphoenzyme with the acid-lability of a histidyl phosphate. In addition to the synthase activity (glycerate-1,3-P2 → glycerate-2,3-P2), kcat 12.5 s?1, the enzyme has bisphosphoglycerate phosphatase activity in the presence of glycolate-2-P (glycerate-2,3-P2 → glycerate-P + Pi), kcat 2.6 s?1 and phosphoglycerate mutase activity (3-PGA ? 2-PGA), kcat 1.7 s?1. The energy of activation for the synthase reaction is 9.38 kcal/mol. Lineweaver-Burk plots of the kinetic data are parallel lines. In contrast intersecting patterns were obtained from similar experiments done with the human red cell enzyme. Further investigation is required to explain these differences. This enzyme may function as both synthase and phosphatase for bisphosphoglycerate in the red blood cell. |
| |
Keywords: | 3-PGA glycerate-3-P 1 3-DPG 2 3-DPG TES DEAE diethylaminoethyl ACD acid-citrate dextrose |
本文献已被 ScienceDirect 等数据库收录! |
|