Functions of nucleotide binding subunits in the tonoplast ATPase from Beta vulgaris L
Partial purification of NO/sub 3/ sensitive H/sup +/-ATPases from the vacuolar membranes of high plants reveal two prominent polypeptides of approximately 60 and 70 kDa. Both polypeptides appear to contain nucleotide binding sites. The photoactive affinity analog of ATP, BzATP, cannot be hydrolyzed by the tonoplast ATPase but is a potential inhibitor (apparent K/sub I/ = 11 ..mu..M). /sup 32/P-BzATP was shown to specifically photolabel the 60 kDa polypeptide. In contrast, Mandala and Taiz have shown the photoincorporation of /sup 32/P-azidoATP to the 70 kDa polypeptide. This sterically different photoaffinity probe can be hydrolyzed although with a low affinity. Azido and benzophenone derivatives of the product, ADP, are currently being examined with respect to their inhibition kinetics of, and their photoincorporation into, the tonoplast ATPase from Beta vulgaris L. Kinetic data will be integrated with patterns of photoincorporation using analogs of both substrate and product, in order to illuminate the functions of the two nucleotide binding subunits.
- Research Organization:
- McGill Univ., Montreal, Quebec
- OSTI ID:
- 5433650
- Journal Information:
- Plant Physiol.; (United States), Vol. 80:4; Conference: Annual meeting of the American Society of Plant Physiologists, Baton Rouge, LA, USA, 8-12 Jun 1986
- Country of Publication:
- United States
- Language:
- English
Similar Records
Photoaffinity labeling of the dopamine reuptake carrier protein with 3-azido sup 3 H GBR-12935
Two and 8-azido photoaffinity probes. 1. Enzymatic synthesis, characterization, and biological properties of 2- and 8-azido photoprobes of 2-5A and photolabeling of 2-5A binding proteins
Related Subjects
ATP-ASE
BIOCHEMICAL REACTION KINETICS
STRUCTURE-ACTIVITY RELATIONSHIPS
ADP
BIOLOGICAL FUNCTIONS
ENZYME ACTIVITY
LABELLED COMPOUNDS
PHOSPHORUS 32
PLANTS
PROTEIN STRUCTURE
TRACER TECHNIQUES
ACID ANHYDRASES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
ENZYMES
FUNCTIONS
HYDROLASES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOSPHOHYDROLASES
PHOSPHORUS ISOTOPES
RADIOISOTOPES
REACTION KINETICS
551001* - Physiological Systems- Tracer Techniques