title: Non-thermal effects of a ceramics radiation on reversibility of lactate dehydrogenase reaction.
abstract: Non-thermal effects of a ceramics radiation on reversibility of lactate dehydrogenase reaction have been investigated using the enzyme irradiated on cooling, and a pyruvate/NADH (system I) or a lactate/NAD+ (system II) as substrate. The Km for lactate in the system II using the irradiated enzyme tended to decrease just like balancing with the increase in Km for pyruvate in system I. The Vmax/Km for system II was increased 2.3-fold by the 18-h irradiated enzyme. Each enthalpy and entropy change in system II using the 18-h irradiation of the enzyme was decreased by 21 kJ mol-1, although that in system I was increased by 12 kJ mol-1. From a thermodynamic analysis, it was estimated that solvation of the active center of LDH was promoted and stabilized by the irradiation, and that it caused this regulation of the reversibility of LDH.
authors.affiliation: School of Food and Nutritional Sciences, University of Shizuoka, Yada, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kohashi
authors.forename: Y
authors.initials: Y
authors.lastname: Kasuya
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D002516:Ceramics; D006358:Hot Temperature; D007259:Infrared Rays; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism* / Q000528:radiation effects*; D007773:Lactates / Q000378:metabolism; D009132:Muscles / Q000201:enzymology; D009243:NAD / Q000378:metabolism; D011773:Pyruvates / Q000378:metabolism; D011817:Rabbits; D013816:Thermodynamics
chemical_list: D007773:Lactates; D011773:Pyruvates; D009243:NAD; D007770:L-Lactate Dehydrogenase