title: Effect of thiol compounds on human complement component C4.
abstract: Thiol compounds have been investigated as inhibitors of the covalent binding reaction of human complement protein C4 using Sepharose-C1s as a combined activating and binding surface. o- and p-substituted aminothiophenols are equally effective inhibitors, whereas the m-substituted compound is a less potent inhibitor. The anti-hypertensive drug captopril is also shown to inhibit the covalent binding reaction. A comparison of the effects of these compounds on the covalent binding reaction of isolated C4A and C4B has been made. Results suggest that a Pro-to-Leu substitution in C4B is likely to account for the differences in inhibitory potency of C4B compared with C4A observed with the aromatic inhibitors.
authors.affiliation: Department of Pharmacology, University of Oxford, U.K.
authors.forename: S
authors.initials: S
authors.lastname: Edmonds
authors.forename: A
authors.initials: A
authors.lastname: Gibb
authors.forename: E
authors.initials: E
authors.lastname: Sim
mesh_terms: D000627:Aminophenols / Q000378:metabolism* / Q000494:pharmacology; D001667:Binding, Competitive; D002216:Captopril / Q000378:metabolism / Q000494:pharmacology; D003173:Complement C1s / Q000378:metabolism; D003181:Complement C4 / Q000737:chemistry / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D015934:Complement C4a / Q000187:drug effects / Q000378:metabolism; D015935:Complement C4b / Q000187:drug effects / Q000378:metabolism; D003171:Complement Pathway, Classical / Q000502:physiology*; D006801:Humans; D007536:Isomerism; D010396:Penicillamine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D012685:Sepharose / Q000378:metabolism; D013329:Structure-Activity Relationship; D013438:Sulfhydryl Compounds / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000627:Aminophenols; D003181:Complement C4; D013438:Sulfhydryl Compounds; D015934:Complement C4a; D015935:Complement C4b; D012685:Sepharose; D002216:Captopril; D003173:Complement C1s; D010396:Penicillamine