title: Vicinal dithiol in pig heart mitochondrial F1-ATPase related to thermal or ATP-dependent conformational changes.
abstract: Active F1-ATPase prepared from pig heart mitochondria can react with about 2 mol of DTNB (5,5'-dithiobis-2-nitrobenzoic acid) or CPDS (6,6'-dithiodinicotinic acid). The reactivity of these thiol reagents decreases if ATP is absent or if F1-ATPase has been submitted to thermal treatment that increases the specific activity without eliminating any contaminating protein. Affinity chromatography on a Sepharose-DTNB column has shown that the thermal treatment of F1-ATPase induces a conformational change of the enzyme that completely prevents it from being retained on the column while the normal active enzyme can be specifically bound to the Sepharose-DTNB column. A comparative study of the thiols of F1-ATPase reacting with CPDS measured by spectrophotometric estimation of the thione released from CPDS and by [14C]CPDS binding to F1-ATPase suggests involvement of a vicinal dithiol in active F1-ATPase. After CPDS reaction, this vicinal dithiol may become an internal disulfide bridge.
authors.affiliation: Laboratoire de Biologie et Technologie de Membranes du CNRS, Université Claude Bernard de Lyon I, 43, Bd du 11 Novembre 1918, 69621, Villeurbanne, France.
authors.forename: C
authors.initials: C
authors.lastname: Godinot
authors.forename: A
authors.initials: A
authors.lastname: Di Pietro
authors.forename: B
authors.initials: B
authors.lastname: Blanchy
authors.forename: F
authors.initials: F
authors.lastname: Penin
authors.forename: D C
authors.initials: DC
authors.lastname: Gautheron
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002846:Chromatography, Affinity; D004228:Dithionitrobenzoic Acid; D006358:Hot Temperature; D008928:Mitochondria / Q000201:enzymology*; D015394:Molecular Structure; D009206:Myocardium / Q000166:cytology / Q000201:enzymology*; D009525:Niacin / Q000031:analogs & derivatives; D011487:Protein Conformation; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D013053:Spectrophotometry; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D034421:Sus scrofa
chemical_list: D013438:Sulfhydryl Compounds; C099658:dithionicotinic acid; D009525:Niacin; D000255:Adenosine Triphosphate; D004228:Dithionitrobenzoic Acid; D006180:Proton-Translocating ATPases