Abstract
Experiments performed in our laboratories have revealed that the equilibrium constant, an expression of the relationship between the rate of synthesis and catabolism of ATP, is significantly higher in the newborn than in the adult. This could be due either to a higher turnover rate or to a rate limiting step in the generation of ATP. In order to test the latter alternative, we performed measurements of adenylate kinase, the enzyme which catalyses the phosphorylation of ADP to ATP. The measurements were done on kidneys obtained from guinea pigs (4-7 days and 6-8 weeks of age). Tissue extract was obtained by homogenizing the kidney and centrifuging it at 100,000 x g. The supernate was used for the enzyme assay. Activity was measured spectrophotometrically by coupling ADP with glucose, hexokinase, glucose-6-phosphate-dehydrogenase and NADP and monitoring formation of NADPH at 340 mu. The results (meanĀ±SE) are expressed in umoles ATP formed/min (unit) per mg protein.
The results demonstrate that the amount of adenylate kinase per mg of protein is similar in the newborn and the adult guinea pig. Thus, the higher equilibrium constant observed in the kidney of the newborn should reflect a higher turnover rate of the adenine nucleotides.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kumar, A., Spitzer, A. ADENYLATE KINASE ACTIVITY IN THE KIDNEY OF DEVELOPING GUINEA PIG. Pediatr Res 18 (Suppl 4), 371 (1984). https://doi.org/10.1203/00006450-198404001-01666
Issue Date:
DOI: https://doi.org/10.1203/00006450-198404001-01666