title: Enzyme kinetic parameters are not altered by microgravity.
abstract: This paper deals with a microgravity experiment concerning the EMEC project (Effect of Microgravity on Enzymatic Catalysis), performed during the parabolic flight of the sounding rocket MASER 7, launched from the base of Esrange (Kiruna, Sweden) on May 3, 1996. The experiment consisted of performing, in a microgravity environment, a number of velocity measurements of an enzyme (isocitrate lyase) catalyzed reaction at different substrate concentrations, to calculate the kinetic parameters (Km and Vmax), which were compared with those obtained at standard gravity, with identical instrumentation. The experimental hardware, the EMEC module, expressly set up by Officine Galileo (Firenze, Italy) with the financial support of the European Space Agency, was a multichannel fibre-optics radiometer, equipped with an automatic injection system, that allowed to measure simultaneously the transmittance changes in 16 reaction cells. The results indicated that under the experimental conditions applied, microgravity has no appreciable effect on the enzyme kinetic constants.
authors.affiliation: Department of Biochemical Sciences, Viale Morgagni, Firenze, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Giachetti
authors.forename: F
authors.initials: F
authors.lastname: Ranaldi
authors.forename: A
authors.initials: A
authors.lastname: Fiusco
authors.forename: M
authors.initials: M
authors.lastname: Tacconi
authors.forename: R
authors.initials: R
authors.lastname: Veratti
authors.forename: P
authors.initials: P
authors.lastname: Falciani
authors.forename: P
authors.initials: P
authors.lastname: Vanni
mesh_terms: D002384:Catalysis; D004867:Equipment Design; D007522:Isocitrate Lyase / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D010659:Phenylhydrazines / Q000494:pharmacology; D013026:Space Flight / Q000295:instrumentation*; D013379:Substrate Specificity; D014893:Weightlessness
chemical_list: D010659:Phenylhydrazines; C030299:phenylhydrazine; D007522:Isocitrate Lyase