Activation energy of serum 5'-nucleotidase as a marker for enzyme heterogeneity
Sogo, M.T.; Gigirey, M.D.; Tutor, J.C.
European Journal of Clinical Chemistry and Clinical Biochemistry 32(12): 905-908
1994
ISSN/ISBN: 0939-4974 PMID: 7696438 Document Number: 425557
Using adenosine 5'-monophosphate (Arkesteijn; J. Clin. Chem. Clin. Biochem. 14 (1976) 155) and inosine 5'-monophosphate (Bertrand and Buret; Clin. Chim. Acta 119 (1982) 275) as substrates for the determination of serum 5'-nucleotidase, linear Arrhenius plots were obtained between 25 degree C and 37 degree C. With the latter method, in patients with hepatobiliary disease, activation energy is higher than in healthy subjects (67.8 +- 0.8 kJ cntdot mol-1 vs. 59.2 +- 1.6 kJ cntdot mol-1, p lt 0.001). Neuraminidase treatment resulted in a significant reduction in the activation energy of serum 5'-nucleotidase from patients (63.6 +- 0.6 kJ cntdot mol-1, p lt 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.