title: [Liver and brain guinea-pig guanine aminohydrolase (author's transl)].
abstract: Guinea-pig brain guanine aminohydrolase (E.C. 3.5.4.3) (M = 120,000 +/- 5,000 daltons) only exhibited one active electrophoretic band; its mobility is similar with that observed for the guinea-pig liver molecular form III. Both forms appear to have coincident activity with pH, as well as an analogous thermal stability and Km values with different substrates showing a different behaviour with the molecular form I of guinea-pig liver enzyme. Brain guanine aminohydrolase and liver molecular form III have similar pK'a values suggesting the participation of histidine and cysteine (-SH) in the enzymatic catalysis. The competitive inhibition by p-chloromercuribenzoate may corroborate the intervention of the last-one.
mesh_terms: D000619:Aminohydrolases / Q000032:analysis*; D000818:Animals; D001921:Brain / Q000201:enzymology* / Q000378:metabolism; D001923:Brain Chemistry; D002499:Centrifugation, Density Gradient; D004591:Electrophoresis, Polyacrylamide Gel; D006148:Guanine Deaminase / Q000032:analysis* / Q000378:metabolism; D006168:Guinea Pigs; D007700:Kinetics; D008099:Liver / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D008970:Molecular Weight
chemical_list: D000619:Aminohydrolases; D006148:Guanine Deaminase
vernacular_title: Guanina aminohidrolasa de hígado y de cerebro de cobaya.