PEROXINECTIN, A NOVEL CELL-ADHESION PROTEIN FROM CRAYFISH BLOOD

From blood cells of the crayfish Pacifastacus leniusculus a 76-kDa pro tein that mediated attachment and spreading of the crayfish blood cell s was purified. The cDNA for this cell adhesion protein was isolated, cloned, and sequenced. The deduced protein sequence was significantly similar to one family of peroxidases, e.g.,myeloperoxidase. Consistent ly, the 76-kDa protein, for which we propose the name peroxinectin, ha d peroxidase activity. A synthetic peptide derived from the peroxinect in sequence containing Lys-Gly-Asp mimicked the cellular activity of t he intact protein, implicating this sequence as the cell-binding site. Peroxinectin is the first cell adhesion molecule cloned from inverteb rate blood and, to our knowledge, the first protein from any organism that combines being a cell adhesion ligand and a peroxidase. (C) 1995 Academic Press, Inc.