The effect of secretagogues on protein carboxyl methylation in the rat brain

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5406602

Bjorndahl, J M

The influence of various substrates which are known to alter free intracellular calcium concentrations on protein carboxyl methyltransferase (PCM) activity was investigated in rat brain synaptosomes. The synaptosomes were labeled with ({sup 3}H)-L-methionine and the {sup 3}H-methyl esters of proteins were formed from the methyl donor ({sup 3}H)-S-adenosyl-L-methionine (({sup 3}H)-AdoMet). The calcium ionophore A23187 and ouabain decreased PCM activity and the decrease produced by A23187 was antagonized by ethylene glycol bis({beta}-aminoethyl ether)-N,N{prime}-tetraacetic acid (EGTA) and MnCl{sub 2}. On the other hand, ruthenium red, an inhibitor of calcium uptake, stimulated PCM activity. These data suggest that PCM activity is inversely related to the free cytoplasmic calcium concentration. Veratridine, A23187 and elevated potassium ions decreased the levels of ATP and ({sup 3}H)-AdoMet. The A23187-mediated decrease in ATP levels and the reduced ({sup 3}H)-AdoMet formation was antagonized by EGTA and MnCl{sub 2}. Inhibition of metabolic activity of the synaptosomes by NaCN led to: (1) decreased ATP levels; (2) inhibition of ({sup 3}H)-AdoMet formation; and (3) inhibition of PCM activity. Four endogenously methylated proteins were isolated from synaptosomes by acidic gel electrophoresis.

• Research Organization: Kansas State Univ., Manhattan, KS (USA)
• OSTI ID: 5406602
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
ALKALINE EARTH METALS
AMINO ACIDS
ANIMAL CELLS
ANIMALS
ATP
BIOCHEMISTRY
BIOSYNTHESIS
BODY
BRAIN
CALCIUM
CARBOXYLIC ACIDS
CENTRAL NERVOUS SYSTEM
CHELATING AGENTS
CHEMICAL REACTIONS
CHEMISTRY
DRUGS
EGTA
ELECTROPHORESIS
ELEMENTS
ENZYME ACTIVITY
ENZYMES
GLYCOLS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INHIBITION
ISOTOPE APPLICATIONS
LIPOTROPIC FACTORS
MAMMALS
METALS
METHIONINE
METHYL TRANSFERASES
METHYLATION
NERVE CELLS
NERVOUS SYSTEM
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PROTEINS
RATS
RODENTS
SOMATIC CELLS
SUBSTRATES
SYNTHESIS
TRACER TECHNIQUES
TRANSFERASES
TRITIUM COMPOUNDS
VERTEBRATES