title: Comparison of low-molecular-weight products following reaction of C3-C3b with C3b inactivator and with trypsin.
abstract: Substitution of trypsin for Konglutinogen-activating factor (KAF) in the procedure for cleaving C3d from C3-C3b substrate produced a relatively heterogeneous low-molecular-weight fraction (C3d-Tryp) which differed in a number of ways from the KAF-mediated cleavage product (C3d-KAF). The differences were demonstrable by agar and polyacrylamide gel electrophoresis, 125I-labelling, content of immunoreactive 125I-labelled C3d, inhibition of anti-complement antiglobulin reagents and rabbit immunization. By comparison with C3d-KAF, the C3d in C3d-Tryp was more heterogeneous and exhibited a faster electrophoretic mobility in agar at pH 8.6. By contrast to C3d-KAF, C3d-Tryp contained protein carrying C3c antigenic determinants.
mesh_terms: D003176:Complement C3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003168:Complement Fixation Tests; D003165:Complement System Proteins / Q000378:metabolism*; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes; D008970:Molecular Weight; D014357:Trypsin
chemical_list: D003176:Complement C3; D000939:Epitopes; D003165:Complement System Proteins; D014357:Trypsin