Flux of the L-serine metabolism in rat liver. The predominant contribution of serine dehydratase.
L-Serine metabolism in rat liver was investigated, focusing on the relative contributions of the three pathways, one initiated by L-serine dehydratase ( SDH), another by serine:pyruvate/alanine:glyoxylate aminotransferase ( SPT/ AGT), and the other involving serine hydroxymethyltransferase and the mitochondrial glycine cleavage enzyme system ( GCS). Because serine hydroxymethyltransferase is responsible for the interconversion between serine and glycine, SDH, SPT/ AGT, and GCS were considered to be the metabolic exits of the serine-glycine pool. In vitro, flux through SDH was predominant in both 24-h starved and glucagon-treated rats. Flux through SPT/ AGT was enhanced by glucagon administration, but even after the induction, its contribution under quasi-physiological conditions (1 mM L-serine and 0.25 mM pyruvate) was about (1)/(10) of that through SDH. Flux through GCS accounted for only several percent of the amount of L-serine metabolized. Relative contributions of SDH and SPT/ AGT to gluconeogenesis from L-serine were evaluated in vivo based on the principle that 3H at the 3 position of L-serine is mostly removed in the SDH pathway, whereas it is largely retained in the SPT/ AGT pathway. The results showed that SPT/ AGT contributed only 10-20% even after the enhancement of its activity by glucagon. These results suggested that SDH is the major metabolic exit of L-serine in rat liver.[1]References
- Flux of the L-serine metabolism in rat liver. The predominant contribution of serine dehydratase. Xue, H.H., Fujie, M., Sakaguchi, T., Oda, T., Ogawa, H., Kneer, N.M., Lardy, H.A., Ichiyama, A. J. Biol. Chem. (1999) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Useapsburg