title: Activation energy of serum 5'-nucleotidase as a marker for enzyme heterogeneity.
abstract: Using adenosine 5'-monophosphate (Arkesteijn; J. Clin. Chem. Clin. Biochem. 14 (1976) 155) and inosine 5'-monophosphate (Bertrand & Buret; Clin. Chim. Acta 119 (1982) 275) as substrates for the determination of serum 5'-nucleotidase, linear Arrhenius plots were obtained between 25 degrees C and 37 degrees C. With the latter method, in patients with hepatobiliary disease, activation energy is higher than in healthy subjects (67.8 +/- 0.8 kJ.mol-1 vs. 59.2 +/- 1.6 kJ.mol-1, p < 0.001). Neuraminidase treatment resulted in a significant reduction in the activation energy of serum 5'-nucleotidase from patients (63.6 +/- 0.6 kJ.mol-1, p < 0.001). Although the activation energy seen is also influenced by conditions other than sialic acid content, the results obtained are in accordance with the hypothesis that in liver disease serum 5'-nucleotidase becomes more sialylated.
authors.affiliation: Laboratorio Central, Hospital General de Galicia, Clínico Universitario, Santiago de Compostela, Spain.
authors.forename: M T
authors.initials: MT
authors.lastname: Sogo
authors.forename: M D
authors.initials: MD
authors.lastname: Gigirey
authors.forename: J C
authors.initials: JC
authors.lastname: Tutor
mesh_terms: D015720:5'-Nucleotidase / Q000097:blood*; D000249:Adenosine Monophosphate / Q000378:metabolism; D001660:Biliary Tract Diseases / Q000201:enzymology; D015415:Biomarkers / Q000097:blood; D004789:Enzyme Activation; D006801:Humans; D007291:Inosine Monophosphate / Q000378:metabolism; D007700:Kinetics; D008107:Liver Diseases / Q000201:enzymology; D019158:N-Acetylneuraminic Acid; D009439:Neuraminidase / Q000378:metabolism; D012794:Sialic Acids / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D015415:Biomarkers; D012794:Sialic Acids; D007291:Inosine Monophosphate; D000249:Adenosine Monophosphate; D015720:5'-Nucleotidase; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid