Proton pumping kinetics and origin of nitrate inhibition of tonoplast-type H+-ATPase

Journal Article · Sat Aug 01 00:00:00 EDT 1987 · Arch. Biochem. Biophys.; (United States)

DOI:https://doi.org/10.1016/0003-9861(87)90620-5· OSTI ID:5956409

Tu, S I; Nagahashi, G; Brouillette, J N

A tonoplast-type vesicle preparation, substantially free from other subcellular membranes, was obtained from corn roots by equilibrium sucrose density gradient centrifugation. At pH 6.5 and in the presence of chloride ions, the tonoplast-type ATPase activity as measured by Pi release, was inhibited by nitrate ions. The ATPase activity was insensitive to molybdate and vanadate, indicating a minimum nonspecific phosphatase and plasma membrane contamination. The vesicles exhibited an ATP hydrolysis-supported proton uptake which was measured by the absorption change of acridine orange. The ATP hydrolysis supported uptake and the subsequent perturbant-induced release of protons (decay) was described by a kinetic model which was previously developed to evaluate the coupling between proton pumping and the primary energy yielding process for other biomembranes. The proton pumping activity was more sensitive to nitrate ions then was ATP hydrolysis. The differential effect and the kinetic analysis of nitrate inhibition led us to suggest that (i) the coupling between Pi release and proton pumping was indirect in nature and (ii) the primary inhibitory effect of nitrate ion was originated from an interaction with a protogenic protein domain which is functionally linked to the ATPase in the tonoplast-type membrane.

• Research Organization: Eastern Regional Research Center, Philadelphia, PA
• OSTI ID: 5956409
• Journal Information: Arch. Biochem. Biophys.; (United States), Vol. 256:2
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ATP
METABOLISM
ATP-ASE
ENZYME ACTIVITY
NITRATES
BIOLOGICAL EFFECTS
PROTONS
MEMBRANE TRANSPORT
CELL MEMBRANES
INHIBITION
MAIZE
MATHEMATICAL MODELS
MOLYBDENUM
PHOSPHATES
ROOTS
VANADIUM
ACID ANHYDRASES
BARYONS
CELL CONSTITUENTS
CEREALS
ELEMENTARY PARTICLES
ELEMENTS
ENZYMES
FERMIONS
GRASS
HADRONS
HYDROLASES
MEMBRANES
METALS
NITROGEN COMPOUNDS
NUCLEONS
NUCLEOTIDES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHOHYDROLASES
PHOSPHORUS COMPOUNDS
PLANTS
TRANSITION ELEMENTS
560300* - Chemicals Metabolism & Toxicology