[Subcellular distribution of arginase and gamma-guanidino-butyrate-ureohydrolase in brain sections, neurons and glia].

Distribution of arginase and gamma-guanidine-butyrate-ureohydrolase in seven brain sections is studied. Specific activity of arginase in brain sections is 0.063-0.117 and of gamma-guanidine-butyrate-ureohydrolase -- 0.042-0.050 mcmoles of urea per 1 mg of protein for 30 min. Cortex and cerebellum neurons have the same arginase activity (0.12 mcmole/mg). Specific arginase activity in glial cerebellum cells is 3 times as much as in cortex glial cells (0.20 and 0.07 mcmole/mg respectively). The activity of gamma-guanidine-butyrate-ureohydrolase in glial cell is higher than in neurons. Subcellular distribution of both enzymes is studied in those brain sections where their activity is maximal. In cerebellum both enzymes were tested, in cortex -- gamma-guanidine-butyrate-ureohydrolase, in thalamus -- arginase. The highest specific arginase activity is found in cytoplasmic, microsomic and synaptosomic fractions. Gamma-Guanidine-butyrate-ureohydrolase is concentrated in cytoplasmic and synaptosomic fractions. Possible correlation of gamma-aminobutyric acid metabolism and participation of brain arginase in regulation of protein biosynthesis are discussed.