title: The mechanism of calcium transport in mitochondria isolated from the marine mussel, Mytilus edulis (L.).
abstract: Isolated mussel mitochondria produced a less pronounced transient stimulation of respiration upon the addition of Ca2+ in a reaction medium containing Pi and a slower rate of Ca2+ transport compared to rat liver mitochondria. The initial rates of Ca2+ transport in the absence of Pi were more similar and both types of mitochondria possessed a sigmoidal relationship between the initial rate of Ca2+ transport and the free Ca2+ concentration ("Km" approximately 5 microM). Ruthenium red produced an equal maximal inhibition of the initial rate of Ca2+ transport in both types of mitochondria but mussel mitochondria were rather more resistant to the inhibitor. The major difference found was that approximately 15 nmoles La3+ mg protein-1 was required to produce maximal inhibition of the initial rate of Ca2+ transport in mussel mitochondria compared to approximately 1.0 nmole La3+ mg protein-1 in rat liver mitochondria. It is concluded that mussel mitochondria possess a comparable Ca2+ transporter to vertebrate mitochondria and possible reasons for resistance to La3+ are discussed.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D049872:Bivalvia / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D004064:Digestive System / Q000378:metabolism; D066298:In Vitro Techniques; D007811:Lanthanum / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism; D010710:Phosphates / Q000494:pharmacology; D051381:Rats; D012430:Ruthenium Red / Q000494:pharmacology; D013045:Species Specificity
chemical_list: D010710:Phosphates; D012430:Ruthenium Red; D007811:Lanthanum; D002118:Calcium