Probing the functional subunits of the tonoplast H/sup +/-ATPase

Conference · Tue Apr 01 04:00:00 EST 1986 · Plant Physiol.; (United States)

OSTI ID:5498415

Randall, S K; Lai, S; Sze, H

The tonoplast ATPase of oat roots is composed of at least three polypeptides of 72, 60, and 16 kDa. The 16 kDA polypeptide covalently binds N,N'-dicyclohexylcarbodiimide and is postulated to be a component of the proton channel. Initial studies to identify other subunits indicate that both the 72 and 60 kDa subunits covalently bind /sup 14/C)-7-chloro-4-nitrobenzo-2-oxa-1,3-diazole and (/sup 14/C)N-ethylamleimide, inhibitors of the tonoplast ATPase. ATP prevents binding of these inhibitors suggesting that both the 72 and 60 kDa subunits are involved in substrate binding. Polyclonal antibody has been made to the 72 kDa subunit. Western blot analysis of tonoplast vesicles reveals single reactive polypeptide (72 kDa). The antibody shows no cross-reactivity towards either the mitochondrial F/sub 1/-ATPase or the plasma membrane ATPase. This antibody specifically inhibits ATP hydrolysis and ATP-dependent H/sup +/ pumping in native tonoplast vesicles. The authors conclude that the 72 kDa subunit is intimately associated with the catalytic (or ATP-binding) site.

• Research Organization: Univ. of Maryland, College Park
• OSTI ID: 5498415
• Conference Information: Journal Name: Plant Physiol.; (United States) Journal Volume: 80:4
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ANTIGEN-ANTIBODY REACTIONS
ATP
ATP-ASE
BIOCHEMICAL REACTION KINETICS
BIOLOGY
CARBON 14 COMPOUNDS
CEREALS
ENZYME INHIBITORS
ENZYMES
GRASS
HYDROLASES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
NUCLEOTIDES
OATS
ORGANIC COMPOUNDS
PHOSPHOHYDROLASES
PLANTS
PROTEIN STRUCTURE
REACTION KINETICS
ROOTS
TRACER TECHNIQUES