The objectives of the proposed research are to study the mechanisms and regulation of neurotransmitter biosynthesis and uptake in the mammalian central nervous system. It is proposed to continue the biochemical characterization of placental and bovine brain choline acetyltransferase, the enzyme which catalyzes the biosynthesis of the neurotransmitter, acetylcholine. Proposed studies include molecular weight determination, amino acid composition, amino terminal analysis, peptide mapping, and a study of the role of thiol groups and imidazole residues in the catalytic mechanism. It is proposed to continue the biochemical characterization and mechanism of subunit interaction of the bovine brain cyclic AMP-dependent protein kinases. After purification using classical enzyme fractionation and affinity chromatography, biochemical characterization of the catalytic and regulatory subunits is planned. The biochemistry of the uptake, storage and release of the postudated neurotransmitters gamma-aminobutyric acid (GABA), norepinephrine, dopamine and acetylcholine in rat brain synaptosomes (pinched-off nerve endings) will also be studied. These studies are related to disease states associated with altered neuronal activity including psychosis, parkinsonism and seizure disorders.