Separate effects of mercurial compounds on the ionophoric and hydrolytic functions of the (Ca/sup + +/ + Mg/sup + +/)-ATPase of sarcoplasmic reticulum. [Skeletal muscle of rabbits]

Journal Article · Wed Jan 01 04:00:00 EST 1975 · J. Membr. Biol.; (United States)

DOI:https://doi.org/10.1007/BF01868568· OSTI ID:7212948

Shamoo, A E; MacLennan, D H

We have shown that a Ca/sup + +/-ionophore activity is present in the (Ca/sup + +/ + Mg/sup + +/)-ATPase of rabbit skeletal muscle sarcoplasmic reticulum. Methylmercuric chloride inhibited the (Ca/sup + +/ + Mg/sup + +/)-ATPase and Ca/sup + +/ transport, but had no effect on the activity of the Ca/sup + +/ ionophore. Mercuric chloride inhibited ATPase, transport and ionophore activity. The ATPase and transport functions were more sensitive to methylmercuric chloride than to mercuric chloride. The two functions were inhibited concomitantly by methylmercuric chloride but slightly lower concentrations of mercuric chloride were required to inhibit Ca/sup + +/ transport than were rquired to inhibit ATPase. Methylmercuric chloride and mercuric chloride probably inhibited ATPase and Ca/sup + +/ transport by blocking essential -SH groups. However, it appears that there are no essential -SH groups in the Ca/sup + +/ ionophore and that mercuric chloride inhibited the Ca/sup + +/ ionophore activity by competition with Ca/sup + +/ for the ionophoric site. Blockage of Ca/sup + +/ transport by mercuric chloride probably occurs both at sites of essential -SH groups and at sites of ionophoric activity. These data suggest the separate identity of the sites of ATP hydrolysis and of Ca/sup + +/ ionophoric activity.

• Research Organization: Univ. of Rochester, NY
• OSTI ID: 7212948
• Journal Information: J. Membr. Biol.; (United States), Journal Name: J. Membr. Biol.; (United States) Vol. 25; ISSN JMBBB
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
ATOMIC IONS
ATP
ATP-ASE
BIOCHEMISTRY
BIOLOGICAL EFFECTS
CALCIUM IONS
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
ELECTROPHORESIS
ENZYMES
ESTERASES
HYDROLASES
HYDROLYSIS
IONS
LYSIS
MAGNESIUM IONS
MAMMALS
MERCURY COMPOUNDS
METABOLISM
METHYLMERCURY
MUSCLES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC MERCURY COMPOUNDS
PHOSPHATASES
RABBITS
RADICALS
SOLVOLYSIS
SULFHYDRYL RADICALS
VERTEBRATES