Source:http://linkedlifedata.com/resource/umls/id/C0009521
NCI: Smaller fragment formed when C5 convertase splits C5 into C5a and C5b. C5a is a 74-amino acid peptide that includes a carboxy-terminal arginine crucial for its spasmogenic activity and a carbohydrate moiety. Initiates the spontaneous assembly of the late complement components, C5-C9, into the membrane attack complex. C5a is the most potent anaphylatoxin, mediating immediate hypersensitivity. C5a is also chemotactic for neutrophils and monocytes.,MSH: The minor fragment formed when C5 convertase cleaves C5 into C5a and COMPLEMENT C5B. C5a is a 74-amino-acid glycopeptide with a carboxy-terminal ARGININE that is crucial for its spasmogenic activity. Of all the complement-derived anaphylatoxins, C5a is the most potent in mediating immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE), smooth MUSCLE CONTRACTION; HISTAMINE RELEASE; and migration of LEUKOCYTES to site of INFLAMMATION.