Dicyclohexylcarbodiimide interaction with sarcoplasmic reticulum: inhibition of Ca/sup 2 +/ efflux

Journal Article · Thu May 05 04:00:00 EDT 1988 · J. Biol. Chem.; (United States)

OSTI ID:6771679

Argaman, A; Shoshan-Barmatz, V

Dicyclohexylcarbodiimide (DCCD), a hydrophobic carboxyl reagent, inhibited Ca/sup 2 +/ release from Ca/sup 2 +/-loaded sarcoplasmic reticulum vesicles, induced by elevated pH, tetraphenylboron, ATP + P/sub i/, or membrane modification with acetic anhydride. Under the conditions used, the same concentrations of DCCD were required for inhibition of Ca/sup 2 +/ release, Ca/sup 2 +/-ATPase activity, and Ca/sup 2 +/ uptake. On the other hand, free Ca/sup 2 +/ or alkaline pH prevented the inhibition by DCCD of Ca/sup 2 +/-ATPase and coupled Ca/sup 2 +/ transport but not that of Ca/sup 2 +/ release. Moreover, several hydrophilic carboxyl reagents inhibited Ca/sup 2 +/-APTase but not Ca/sup 2 +/ release. The authors suggest that a carboxyl residue(s), located in a hydrophobic region of a protein(s), is involved in the control of Ca/sup 2 +/ release, where DCCD interaction with this group blocks Ca/sup 2 +/ release. This group is distinct from the one involved in the inhibition of Ca/sup 2 +/-ATPase. DCCD also inhibited (/sup 3/H)ryanodine binding to junctional sarcoplasmic reticulum membranes. The presence of Ca/sup 2 +/ or an alkaline pH only slightly affects the degree of inhibition of ryanodine binding by DCCD. Incubation of the membranes with (/sup 14/C)DCCD resulted in labeling of 350-, 170-, 140-, 53-, and 30-kDa proteins in addition to the Ca/sup 2 +/-ATPase. The involvement of one or all of the DCCD-labeled proteins in Ca/sup 2 +/ release and ryanodine binding is discussed.

• Research Organization: Ben Gurion Univ. of the Negev, Beer Sheva (Israel)
• OSTI ID: 6771679
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 263:13; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ALKALINE EARTH METAL COMPOUNDS
ATP-ASE
BIOCHEMISTRY
CALCIUM COMPOUNDS
CARBON 14 COMPOUNDS
CATIONS
CELL CONSTITUENTS
CHARGED PARTICLES
CHEMISTRY
ENZYMES
HYDROLASES
IMIDES
IONS
LABELLED COMPOUNDS
MEMBRANE TRANSPORT
MUSCLES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
PHOSPHOHYDROLASES
PHYSIOLOGY
SARCOPLASMIC RETICULUM
TRITIUM COMPOUNDS