Reversible inhibition by 4,4'-diisotheiocyanatostilbene-2,2'-disulfonic acid of the plasma membrane (Ca sup 2+ + Mg sup 2+ )ATPase from kidney proximal tubules

Journal Article · Tue Jun 11 00:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00237a010· OSTI ID:5032601

Guilherme, A; Vieyra, A ^[1]; Meyer-Fernandes, J R ^[2]

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1. Univ. Federal do Rio de Janeiro (Brazil)
2. Univ. do Estado do Rio de Janeiro (Brazil)

Calcium accumulation by purified vesicles derived from basolateral membranes of kidney proximal tubules was reversibly inhibited by micromolar concentrations of 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), an inhibitor of anion transport. The inhibitory effect of this compound on Ca{sup 2+} uptake cannot be attributed solely to the inhibition of anion transport. The concentrations needed to attain half-maximal inhibition were 20 and 63 {mu}M for (Ca{sup 2+}+Mg{sup 2+})ATPase and ATP-dependent Ca{sup 2+} transport, respectively. The rate constant of EGTA-induced Ca{sup 2+} efflux from preloaded vesicles was not affected by DIDS, indicating that this compound does not increase the permeability of the membrane vesicles to Ca{sup 2+}. The inhibition by DIDS was eliminated when the free ATP concentration of the medium was raised from 0.3 to 8 mM, possibly due to an increase in the turnover of the enzyme caused by free ATP accelerating the E{sub 2}{yields}E{sub 1} transition, and leading to a decrease in the proportion of E{sub 2} forms under steady-state conditions. Taken as a whole, these results indicate that DIDS interacts with the enzyme in the E{sub 2} conformation, probably slowing the rate of the E{sub 2}{yields}E{sub 1} transition in forward cycles.

• OSTI ID: 5032601
• Journal Information: Biochemistry; (United States), Vol. 30:23; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ATP-ASE
INHIBITION
CALCIUM 45
MEMBRANE TRANSPORT
STILBENE
BIOLOGICAL EFFECTS
ATP
CELL MEMBRANES
ENZYME ACTIVITY
ISOTHIOCYANATES
KIDNEYS
PHOSPHORUS 32
TUBULES
ACID ANHYDRASES
ALKALINE EARTH ISOTOPES
AROMATICS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CALCIUM ISOTOPES
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
ENZYMES
EVEN-ODD NUCLEI
HYDROCARBONS
HYDROLASES
INTERMEDIATE MASS NUCLEI
ISOTOPES
LIGHT NUCLEI
MEMBRANES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PHOSPHOHYDROLASES
PHOSPHORUS ISOTOPES
RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques