RESUMO
Protein kinases tightly associated with chick embryo brain ribosomes washed with Triton X-100 and KCl were characterized by their ability to phosphorylate ribosomes and two exogenous substrates, histone IIA and casein. c-AMP-dependent kinase (PKA) and casein kinases (CK1, CK2) were examined in the presence of specific modulators by SDS/PAGE followed by renaturation in gel assay according to Kameshita & Fujisawa (Anal. Biochem. 1989, 183, 139-143). Basing on these data it can be presumed that PKA activity increases, but the levels of CK2 and CK1 decrease during chick embryo development.
Assuntos
Encéfalo/enzimologia , Proteínas Quinases/isolamento & purificação , Ribossomos/enzimologia , Animais , Encéfalo/metabolismo , Caseína Quinases , Embrião de Galinha , Proteínas Quinases Dependentes de AMP Cíclico/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Isoenzimas/isolamento & purificação , Fosforilação , Proteínas Ribossômicas/metabolismo , Ribossomos/metabolismo , Dodecilsulfato de SódioRESUMO
Cu, Zn-superoxide dismutase (Cu,Zn-SOD), Mn-superoxide dismutase (Mn-SOD), catalase (CAT), peroxidase (POX), glutathione peroxidase(GP) and glutathione reductase (GR) activities were assayed in the brains of genetically selected neurological mutant rabbits pt and their controls. Paralytic tremor (pt) is a spontaneous mutation in rabbit that affects irregular and defective myelination of CNS. Antioxidant enzyme levels were different in three brain regions: brain hemispheres, cerebellum, and brain stem. In brain hemisphere and cerebellum of pt rabbits Mn-SOD and Cu, Zn-SOD activities were elevated. Catalase activity in brain hemispheres and peroxidase activity in the brain stem of pt rabbits were reduced. It was also noticed, that in the pt rabbit the ratio CAT/Cu, Zn-SOD was lower by 20% in the brain hemispheres and by 13% in the cerebellum and the ratio POX/Cu, Zn-SOD was lower by 31.8% in the brain stem. These findings indicated that pt mutations are associated with changes in the antioxidant defense system in the rabbit brain.
Assuntos
Encéfalo/enzimologia , Catalase/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Peroxidase/metabolismo , Animais , Tronco Encefálico/enzimologia , Cerebelo/enzimologia , CoelhosAssuntos
Envelhecimento/metabolismo , Encéfalo/metabolismo , Proteínas Quinases/metabolismo , Animais , Encéfalo/enzimologia , Cálcio/metabolismo , Calmodulina/metabolismo , Humanos , Nucleotídeos Cíclicos/metabolismo , Fosfolipídeos/metabolismo , Proteínas Tirosina Quinases/metabolismo , Serina/metabolismo , Treonina/metabolismoRESUMO
The protein kinase activity in the postmitochondrial and postribosomal fractions from chick brain at various stages of development was examined. It has been found, that the overall level of protein kinases activity, assayable under the experimental conditions, increases during embryogenesis, sharply decreases at the hatch, and again increases thereafter. The subcellular distribution of protein kinases alters during ontogenetic development. The embryonal protein kinases of both subcellular fractions differ in the protein substrate specificity, cAMP- and salts-sensitivity from those of the adult ones. Thanks to use of ribosomal proteins as an exogenous substrates it was possible to visualize the developmental changes in the protein kinase pattern.
Assuntos
Encéfalo/enzimologia , Embrião de Galinha/metabolismo , Galinhas/metabolismo , Proteínas Quinases/metabolismo , Animais , Encéfalo/embriologia , Encéfalo/crescimento & desenvolvimento , Frações Subcelulares/enzimologiaRESUMO
32P-ortophosphate was introduced intraamnionally into 5, 9, 12, 15 and 19 day-old chick embryos. After 4 hours the specific activity of brain and liver ribosomal proteins and their fractions were determined. It was found that the specific activities of those in both tissues were highest at the early stages of development, and they declined rapidly to reach the lowest value at day 19. The observed differences between brain and liver ribosomal proteins are consistent with an unequal rhythm of ontogenesis.
