title: [Nitrogen-economy and synthesis of serine and glycine in reticulocytes].
abstract: Amino acids constitute the main substrate of the reticulocyte. The amino acid pool of reticulocytes represents a characteristic selection. The composition of the amino acid pool is dependent on maturation. From the preferential oxidation of short-chain amino acids one would expect a ratio about of 5:1 between the oxygen consumption and ammonia formation. If one corrects for NH3-formation by the deamination of nucleotides the ratio between the oxygen consumption and NH3-formation is about an order of magnitude higher than the theoretical ratio. The small liberation of NH3 in energy production from amino acids results from the re-utilization of their alpha-NH2-group for the synthesis of serine and glycine, while the C-skeleton stems from glucose. Serine is formed via OH-pyruvate and OH-pyruvate. Serine and glycine serve preferentially for synthesis of hemoglobin. In reticulocytes there exists a compartmentation of glycine which accounts for differences between serine and glycine in isotopic experiments. From the time dependent change of the specific activities of pulse-labelled serine and glycine one may calculate that the serine synthesis amounts to 15--30% of the glucose utilization.
mesh_terms: D005971:Glutamates / Q000494:pharmacology; D005998:Glycine / Q000096:biosynthesis*; D006801:Humans; D009584:Nitrogen / Q000097:blood*; D010101:Oxygen Consumption / Q000187:drug effects; D011773:Pyruvates / Q000494:pharmacology; D012156:Reticulocytes / Q000378:metabolism*; D012694:Serine / Q000096:biosynthesis*
chemical_list: D005971:Glutamates; D011773:Pyruvates; D012694:Serine; D009584:Nitrogen; D005998:Glycine
vernacular_title: Stickstoff-Okonomie und Synthese von Serin und Glyzin in Retikulozyten.