Functional arginine residue in the catalytic site of the tonoplast H/sup +/-ATPase
Phenylglyoxal was used to convalently modify arginine residues of the red beet tonoplast H/sup +/-ATPase. Phenylglyoxal completely inactivated ATPase activity. Inactivation followed pseudo-first-order kinetics with an apparent reaction order near one, suggesting that enzyme inactivation resulted from modification of a single arginine residue per enzyme molecule. Potassium salts of several anions partially protected for phenylglyoxal inactivation by this appeared to be non-specific since anions that stimulate H/sup +/-ATPase activity were not the most effective in protecting activity. Similarly, 100 um DIDS was only slightly effective in protecting from phenylglyoxal inhibition. ATP protected from phenylglyoxal inactivation while ADP did not and phenylglyoxal inhibition decreased the Vmax without effecting the Km for ATP hydrolysis. These results suggest that functional arginine modification occurs at or near the catalytic ATP binding site. Attempts to label this site with (/sup 14/C)phenylglyoxal will be presented.
- Research Organization:
- Univ. of California, Davis
- OSTI ID:
- 5607425
- Report Number(s):
- CONF-8707108-
- Journal Information:
- Plant Physiol., Suppl.; (United States), Vol. 83:4; Conference: Annual meeting of the American Society of Plant Physiologists, St. Louis, MO, USA, 19 Jul 1987
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ATP-ASE
ENZYME INHIBITORS
PROTEIN STRUCTURE
BIOCHEMICAL REACTION KINETICS
ADP
ANIONS
ARGININE
ATP
BEETS
CARBON 14 COMPOUNDS
CATIONS
ENZYME ACTIVITY
POTASSIUM
STRUCTURE-ACTIVITY RELATIONSHIPS
TRACER TECHNIQUES
ACID ANHYDRASES
ALKALI METALS
AMINO ACIDS
CARBOXYLIC ACIDS
CHARGED PARTICLES
ELEMENTS
ENZYMES
FOOD
HYDROLASES
IONS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
METALS
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHOSPHOHYDROLASES
PLANTS
REACTION KINETICS
VEGETABLES
550201* - Biochemistry- Tracer Techniques