Abstract
We present a simplified model of purine de novo synthesis consisting in: (1) the administration of [14C] formate, (2) the determination in the nucleotides, of both concentrations and specific activity, (3) the calculation of the apparent rate constants (k1-k2-k3) for overall reactions involved in IMP, AMP and GMP formation, through a system of differential equations. We have evaluated the channeling of IMP into either GMP or AMP (“the inosinic branch point”) in vivo. The extraction of acid-soluble nucleotides, hydrolysis, purification of purine bases, determination of quantity and specific radioactivity after [14c] formate administration, was carried out according to Pizzichini et al., 1985 (1). In the liver, kidney and other organs, of normal, adrenalectomized, castrated rats, we found (1) a different pattern for each type of tissue, (2) a preferential channeling of IMP into AMP under normal conditions, with remarkable variations in the individual situations. We were able to conclude that this critical metabolic point is under hormonal control.
(1) Pizzichini M., Di Stefano A., Marinello E. (1985) It.J. Bioch. 34(5), 305-312.
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Pizzichini, M., Stefano, A., Resconi, G. et al. 117 THE INOSINIC BRANCH POINT AND ITS HORMONAL REGULATION. EVALUATION THROUGH A MATHEMATICAL MODEL. Pediatr Res 24, 130 (1988). https://doi.org/10.1203/00006450-198807000-00141
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DOI: https://doi.org/10.1203/00006450-198807000-00141