Portal de Periódicos da CAPES

Regulation of the rate of amino acid incorporation into protein by rat liver cell sap components

1969; Elsevier BV; Volume: 56; Issue: 2-3 Linguagem: Inglês

10.1016/0014-4827(69)90019-6

1090-2422

Alexandra von der Decken,

Microbial Metabolic Engineering and Bioproduction

Cell sap from 8 g of liver of non-starved rats was lyophilized, resuspended in a smaller volume and applied to a column of Sephadex G-50. The collected fractions were lyophilized and resuspended in 0.2 ml of distilled water. Part of each fraction was used for thinlayer chromatography (TLC) and the chromatograms were tested for ultraviolet (UV) absorption and for ninhydrin staining. The effect of each fraction on amino acid incorporating activity in the absence and presence of GTP was studied in systems containing ATP, an ATP regenerating system, ribosomes and cell sap from normal rats. The cell sap had been passed through a column of Sephadex G-25 to remove small molecular weight components. Cell sap of normal and carbohydrate-fed rats was separated on the Sephadex G-50 columns into fractions of inhibitory and stimulatory activity. Subfractions of cell sap from stress-induced and protein-fed rats had a low or non-inhibitory activity but a very pronounced stimulatory activity. Fractions of stimulatory activity were characterized further by means of thinlayer chromatography. They contained amino acids and nucleoside triphosphates, primarily ATP and GTP. The fractions of inhibitory activity obtained after column chromatography on Sephadex G-50 contained RNA, protein and lipoid components. The inhibitory activity was retained after thinlayer chromatography in organic solvent. The eluate containing the inhibitory activity showed a decrease in protein content.