Effect of some cardiac and respiratory drugs on succinate-cytochrome c reductase.
Succinate-cytochrome c reductase was inhibited in vitro and in vivo by phenobarbitone, aminophylline and neostigmine using both 2,6-dichlorophenolindophenol (DCIP) and cytochrome c (cyt c) as substrates. The enzyme was also activated by gallamine towards both substrates. In vitro, phenobarbitone and aminophylline inhibited the enzyme with respect to the reduction of DCIP and cyt c in a non-competitive manner with Ki values of 1.5 x 10(-5) and 5.7 x 10(-5)M, respectively. Moreover, neostigmine competitively inhibited the enzyme towards both substrates with Ki values of 1.36 x 10(-5) and 1.50 x 10(-5)M, respectively.
Balbaa
Mahmoud
M
Department of Chemistry, College of Science, Qatar University, P.O. Box 2713, Doha, Qatar. m_balbaa@hotmail.com
Al-Meer
Jehan
J
Al-Khal
Amina
A
D000818:Animals; D002317:Cardiovascular Agents / Q000494:pharmacology*; D005703:Gallamine Triethiodide / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D051379:Mice; D015394:Molecular Structure; D009388:Neostigmine / Q000494:pharmacology; D010634:Phenobarbital / Q000494:pharmacology; D019141:Respiratory System Agents / Q000494:pharmacology*; D013384:Succinate Cytochrome c Oxidoreductase / Q000037:antagonists & inhibitors* / Q000302:isolation & purification / Q000378:metabolism; D013806:Theophylline / Q000494:pharmacology
D002317:Cardiovascular Agents; D019141:Respiratory System Agents; D009388:Neostigmine; D013806:Theophylline; D013384:Succinate Cytochrome c Oxidoreductase; D005703:Gallamine Triethiodide; D010634:Phenobarbital