Phosphoglycerate kinase deficiency: biochemical studies on hair follicles

A fluorimetric procedure for the determination of phosphoglycerate kinase in single human hair follicles is described. Enzyme studies on different parts of hair follicles after dissection show that the distribution of glucose-6-phosphate dehydrogenase matches that of phosphoglycerate kinase. Glucose-6-phosphate dehydrogenase can therefore be used as a reference enzyme to compensate for differences in hair follicle sizes. It was shown that the variation in the values found in individual hair follicles is improved by relating phosphoglycerate kinase to glucose-6-phosphate dehydrogenase activity. In areas of the world where glucose-6-phosphate dehydrogenase deficiency occurs frequently, an autosomally inherited reference enzyme may be preferred. It is shown that 6-phosphogluconate dehydrogenase is useful in this respect. Upon storage a gradual drop in the activity of all three enzymes was observed, but the rate of decrease was about equal: the enzyme activity ratio was, therefore, almost unaffected for a period of one week. This allows the determination of phosphoglycerate kinase even in mailed hair follicles.