Arutyunov D Y, Muronetz V I
A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia.
Biochem Biophys Res Commun. 2003 Jan 3;300(1):149-54. doi: 10.1016/s0006-291x(02)02802-4.
Influence of non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN) on glycolysis was investigated. The addition of GAPN-which oxidizes glyceraldehyde-3-phosphate directly to the 3-phosphoglyceric acid-led to the strong increase in the rate of lactate accumulation in the rat muscle extract with low ADP content. The lactate accumulation was also observed in the presence of GAPN in rat muscle extract, which contained only ATP and no ADP. This can be the evidence of the "futile cycle" stimulated by GAPN. Here ADP can be regenerated from ATP by the phosphoglycerate kinase reaction. The high resistance of GAPN from Streptococcus mutans towards inactivation by natural oxidant-H(2)O(2) was showed. This feature distinguishes GAPN from phosphorylating glyceraldehyde-3-phosphate dehydrogenase, which is very sensitive to modification by hydrogen peroxide. A possible role of the oxidants and non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase in the regulation of glycolysis is discussed.
研究了非磷酸化甘油醛-3-磷酸脱氢酶（GAPN）对糖酵解的影响。添加GAPN（它将甘油醛-3-磷酸直接氧化为3-磷酸甘油酸）导致低ADP含量的大鼠肌肉提取物中乳酸积累速率大幅增加。在仅含有ATP而无ADP的大鼠肌肉提取物中，存在GAPN时也观察到了乳酸积累。这可能是GAPN刺激“无效循环”的证据。在此，ADP可通过磷酸甘油酸激酶反应从ATP再生。显示了变形链球菌的GAPN对天然氧化剂H₂O₂失活具有高抗性。这一特性将GAPN与对过氧化氢修饰非常敏感的磷酸化甘油醛-3-磷酸脱氢酶区分开来。讨论了氧化剂和非磷酸化甘油醛-3-磷酸脱氢酶在糖酵解调节中的可能作用。
