RESUMO
Lysosomal alpha-d-mannosidase from mouse tissues was separated into its constituent isoenzymes by DEAE-cellulose chromatography. Forms corresponding to the human isoenzymes B and A were present in testis, brain, spleen and kidney, whereas in epididymis and liver only the B form was present. Murine alpha-mannosidases A and B are glycoproteins and have pH optima, thermal stabilities and molecular masses similar to those of the human isoenzymes. A full-length cDNA (3.1 kb) containing the complete coding sequence for alpha-mannosidase was isolated from a mouse macrophage cDNA library. Comparison of the deduced amino acid sequences of human and mouse alpha-mannosidases showed that they had 75% identity and 83% similarity. Expression of this cDNA in COS cells showed that both the A and the B isoenzymes can arise from a single transcript. Northern blotting analysis showed a 10-fold range in the abundance of alpha-mannosidase mRNA in mouse tissues, with the highest levels found in epididymis, and the lowest in liver.
Assuntos
Isoenzimas/química , Lisossomos/enzimologia , Manosidases/química , Manosidases/genética , Sequência de Aminoácidos , Animais , Northern Blotting , Células COS , Cromatografia DEAE-Celulose , Mapeamento Cromossômico , Clonagem Molecular , DNA Complementar/genética , Expressão Gênica , Humanos , Isoenzimas/genética , Isoenzimas/isolamento & purificação , Isoenzimas/metabolismo , Manosidases/isolamento & purificação , Manosidases/metabolismo , Camundongos , Dados de Sequência Molecular , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Homologia de Sequência de Aminoácidos , alfa-ManosidaseRESUMO
The effect of section of the rostral hepatic nerve (RNH), branch of the left abdominal vagus, on the circadian rhythm of tyrosine transaminase (TAT) activity in rat liver has been investigated. It has been shown that the midnight peak of TAT activity is suppressed after section of the rostral hepatic nerve and by subdiaphragmatic vagotomy, but is unaffected by sham-operation and section of the ventral abdominal vagus caudal to the emergence of the rostral hepatic nerve. It is concluded that the rhythm of TAT activity is under neural control, either directly or reflexely.