RESUMO
Arginase (EC 3.5.3.1) from human liver. kidney, mammary gland, and erythrocytes, was separated by agar-gel electrophoresis using barbital buffer pH 8.6. Three isoenzymes were separated. Two of these, A2 and A3, occur in liver and erythrocytes. The same two isoenzymes were found in the kidney, but in reversed proportions. In addition to the A3 isoenzyme, the mammary gland contains a fast anodically moving A1 isoenzyme. The three isoenzymes differ in their degree of sensitivity to ornithine.
Assuntos
Arginase/isolamento & purificação , Isoenzimas/isolamento & purificação , Arginase/antagonistas & inibidores , Mama/enzimologia , Eletroforese em Gel de Ágar , Eritrócitos/enzimologia , Feminino , Humanos , Rim/enzimologia , Fígado/enzimologia , Ornitina/farmacologiaRESUMO
The metabolism of tryptophan (TRP) was studied in diabetic and insulin-treated diabetic rats throughout a five-month period. In alloxan diabetic rats the serum and brain TRP levels were decreased (serum: 38 to 48 mmol/l, brain: 8.6 to 9.2 mmol/g) in comparison to the values of control rats (serum: 59 to 64 mmol/l, brain: 11.3 to 12.6 mmol/g). Daily long-term (for 45, 75, 90 or 135 days) treatment with intermediately acting insulin (4 IU/rat, s.c.) was not able to restore brain concentration of TRP. On the contrary, the serum TRP concentrations were totally or partially restored. The concentrations of branched chain amino acids (BCAA) were increased in serum (valine = 361.2 to 461.0 mumol/l or leucine + isoleucine = 431.0 to 520.3 mumol/l) throughout the entire five-month examination period. Insulin treatment did not return serum concentration of BCAA to normal level in the observation period either.