Cavener D R, Clegg M T
Proc Natl Acad Sci U S A. 1981 Jul;78(7):4444-7. doi: 10.1073/pnas.78.7.4444.
The in vivo flux of carbon through the pentose shunt is investigated as a function of different 6-phosphogluconate dehydrogenase (6Pgd) and glucose-6-phosphate dehydrogenase (G6pd) genotypes by using differential radioactive labeling of the C-1 and C-6 positions of glucose. Alternative 6Pgd-G6pd genotypes are shown to differ in relative in vivo carbon flux through the pentose shunt. The relative in vitro specific activity differences between the 6PgdSS and 6PgdFF genotypes appear to be primarily responsible for these differences. In addition, the pentose-shunt activity is correlated with the rate of lipid synthesis. This correlation is consistent with the major metabolic function of the pathway, which is to produce NADPH for lipid synthesis. Taken together, the results of these experiments show that different genotypes of 6Pgd are associated with measurable biochemical and physiological differences. Higher order phenotypic differences of this kind must be demonstrated to support the hypothesis that natural selection can discriminate among allozymes of a given genetic locus.
通过对葡萄糖C-1和C-6位进行差异放射性标记，研究了戊糖磷酸途径中碳的体内通量与不同6-磷酸葡萄糖酸脱氢酶（6Pgd）和葡萄糖-6-磷酸脱氢酶（G6pd）基因型的关系。结果表明，不同的6Pgd-G6pd基因型在戊糖磷酸途径中的相对体内碳通量存在差异。6PgdSS和6PgdFF基因型之间的相对体外比活性差异似乎是造成这些差异的主要原因。此外，戊糖磷酸途径的活性与脂质合成速率相关。这种相关性与该途径的主要代谢功能一致，即产生用于脂质合成的NADPH。综上所述，这些实验结果表明，6Pgd的不同基因型与可测量的生化和生理差异相关。必须证明这种高阶表型差异，以支持自然选择能够区分给定基因座的等位酶这一假设。
