The soluble calcium-binding protein from muscle of the sandworm, Nereis virens.
Fast-acting muscle of the sandworm, Nereis virens, contains one soluble calcium-binding protein having a molecular weight close to 17 000 and occurring in the muscle at a concentration of approximately 0.1 mM. The protein binds two Ca2+ at equivalent sites with dissociation constant Kd = 6.4 X 10(-7) M. Its N-terminal amino acid is blocked by an N-acetyl group whereas glycine is the C-terminal residue. The comparison of the tryptic peptide map of this protein with those of the soluble calcium-binding protein from crayfish muscle, bovine brain calmodulin and rabbit skeletal muscle troponin C suggests that all of these proteins are homologous. Sandworm calcium-binding protein therefore belongs to the so-called cytosolic calcium EF-hand family. This protein is presumably the functional counterpart of vertebrate parvalbumin acting as soluble relaxing factor.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000845:Annelida / Q000032:analysis*; D017317:Annexin A6; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D007526:Isoelectric Point; D008970:Molecular Weight; D009124:Muscle Proteins / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism
D000596:Amino Acids; D017317:Annexin A6; D002135:Calcium-Binding Proteins; D009124:Muscle Proteins; D002118:Calcium