Isolation and properties of Ca2+-transporting glycoprotein and peptide from beef heart mitochondria.
The 40,000-dalton glycoprotein and 2000-dalton peptide inducing selective Ca2+-transport through bilayer lipid membranes were isolated from beef heart homogenate and mitochondria. Micromolar concentrations of these substances were found to increase the conductivity of membranes by 3-4 orders. Trans-membrane Ca2+ gradient induces an electric potential difference whose magnitude is close to the theoretical for ideal Ca2+ selectivity. The inhibitor of mitochondrial Ca2+ transport, ruthenium red, abolishes both the glycoprotein- and peptide-induced Ca2+ transport in bilayer lipid membranes. Thiol groups essential for Ca2+ transport activity were revealed in the glycoprotein and peptide. Addition of these substances to rat liver mitochondria induces Ca2+-dependent inhibition of the state 3 respiration that can be released by uncouplers (oligomycin-like effect).
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002417:Cattle; D004229:Dithiothreitol / Q000494:pharmacology; D006023:Glycoproteins / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008051:Lipid Bilayers; D008929:Mitochondria, Heart / Q000378:metabolism*; D008970:Molecular Weight; D010455:Peptides / Q000302:isolation & purification / Q000378:metabolism
D000596:Amino Acids; D002352:Carrier Proteins; D006023:Glycoproteins; D008051:Lipid Bilayers; D010455:Peptides; D002118:Calcium; D004229:Dithiothreitol