title: Chemotactic factor for tumor cells derived from the C5a fragment of complement component C5.
abstract: Previously, we have stablished that the fifth component of complement (C5) serves as an important source of mediators that have locomotory (chemotactic) activity for leukocytes and tumor cells. C5a, a fragment (Mr 11,200) derived from the NH2-terminal portion of the alpha chain of C5, is the major chemotactic peptide for leukocytes. The present studies demonstrate that cleavage of C5a with trypsin generates a derivative peptide that is chemotactic for tumor cells (Walker carcinosarcoma). This fragment has an estimated Mr of 6000 as assessed by gel filtration and does not require the COOH-terminal arginine of C5a, because equivalent amounts of chemotactic activity for tumor cells can be generated from des-Arg-C5a by digestion with trypsin. The C5a-derived chemotactic peptide for tumor cells demonstrates peak activity at approximately 1 pM. These studies emphasize the key role of the C5a region of the C5 molecule in the generation of peptides that affect locomotory responses of cells.
mesh_terms: D000818:Animals; D002279:Carcinoma 256, Walker / Q000503:physiopathology*; D002633:Chemotaxis; D003182:Complement C5; D006801:Humans; D008247:Lysosomes / Q000201:enzymology; D051379:Mice; D009504:Neutrophils / Q000502:physiology; D010446:Peptide Fragments; D011817:Rabbits; D014357:Trypsin
chemical_list: D003182:Complement C5; D010446:Peptide Fragments; D014357:Trypsin