Identification of the peptide bond cleaved during activation of human C1r.
CNBr cleavage of unreduced proenzyme C1r yielded fragment CP2b, isolated by gel filtration and high-pressure gel permeation chromatography. This fragment (approximately Mr 55 000) comprised at least 4 disulphide-linked peptides, which were separated by gel filtration after reduction and alkylation. Peptide CP2bRA4, overlapping the A- and B-chain regions in proenzyme C1r was digested by V8 staphylococcal protease, and the digest separated by reversed-phase HPLC. N-terminal sequence analysis of peptide CP2bRA4SP9 established that C1r activation involves the cleavage of a single Arg-Ile bond, located in the sequence: ... Gln-Arg-Gln-Arg-Ile-Ile-Gly-Gly ... .
Arlaud
G J
GJ
Gagnon
J
J
D000596:Amino Acids / Q000032:analysis; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003166:Complement Activating Enzymes / Q000032:analysis*; D015923:Complement C1r; D003488:Cyanogen Bromide; D010450:Endopeptidases / Q000378:metabolism; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D012697:Serine Endopeptidases
D000596:Amino Acids; D010446:Peptide Fragments; D003166:Complement Activating Enzymes; D010450:Endopeptidases; D012697:Serine Endopeptidases; C028344:glutamyl endopeptidase; D015923:Complement C1r; D003488:Cyanogen Bromide