Abstract
Lactoperoxidase is an iron containing enzyme, which is an essential component of the defense system of mammalian secretary fluids. The enzyme readily oxidizes adrenaline and other catecholamines to coloured aminochrome products. A Km-value of 1.21 mM and a catalytic constant (k = V\max/[Enz]) of 15.5 × 103 min−1 characterized the reaction between lactoperoxidase and adrenaline at pH 7.4. Urate was found to activate the enzyme catalyzed oxidation of adrenaline in a competitive manner, the effect decreasing with increasing adrenaline concentration. Lactoperoxidase was able to catalyze the oxidation of urate. However, urate was a much poorer substrate than adrenaline, and it seems unlikely that urate activates by functioning as a free, redox cycling intermediate between enzyme and adrenaline. The activation mechanism probably involves an urate-lactoperoxidase complex.
Similar content being viewed by others
References
Adak S, Bandyopadhyay U, Bandyopadhyay D, Banerjee RK. 1998 Mechanism of horseradish peroxidase catalyzed epinephrine oxidation: obligatory role of endogenous O.2 and H2O2. Biochemistry 37, 16922–16933.
Cleland WW. 1967 The statistical analysis of enzyme kinetic data. Adv Enzym 29, 1–32.
Dixon M, Webb EC. 1979 Enzymes, 3rd edn. New York and San Fransisco: Academic Press.
Ghibaudi E, Laurenti E. 2003 Unraveling the catalytic mechanism of lactoperoxidase and myeloperoxidase. A reflection on some controversial features. Eur J Biochem 270, 4403–4412.
Ferrari RP, Traversa S, De Gioia L, Fantucci P, Suriano G, Ghibaudi EM. 1999 Cathechol(amine)s as probes of lactoperoxidase cata-lytic site structure: spectroscopic and modeling studies. J Biol Inorg Chem 4, 12–20.
Løvstad RA. 1971 Effect of NADH on the ceruloplasmin catalyzed oxidation of dopamine and noradrenaline. Acta Chem Scand 25, 3144–3150.
Løvstad RA. 1979 Activating effect of chlorpromazine on the peroxidase-catalyzed oxidation of catecholamines. Gen Pharmac 10, 437–440.
Løvstad RA. 1980 Interaction of phenothiazine derivatives with horseradish peroxidase and lactoperoxidase. Gen Pharmac 11, 331–336.
Maples KR, Mason RP. 1988 Free radical metabolite of uric acid. J Biol Chem 263, 1709–1712.
Metodiewa D, Reszka K, Dunford HB. 1989 Evidence for a perox-idatic oxidation of norepinephrine, a catecholamine, by lactoper-oxidase. Biochem Biophys Res Commun 160, 1183–1188.
Polis BD, Shmukler HW. 1953 Crystalline lactoperoxidase I. Isol-ation by displacement chromatography II. Physicochemical and enzymatic properties. J BiolChe m201, 475–500.
Szent-Györgyi A. 1960 Introduction to a Submolecular Biology, New York and London: Academic Press.
Wrona MZ, Dryhurst G. 1979 Investigation of the enzymic and elec-trochemical oxidation of uric acid derivatives. Biochim Biophys Acta 570, 372–387.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Løvstad, R.A. Effect of urate on the lactoperoxidase catalyzed oxidation of adrenaline. Biometals 17, 631–634 (2004). https://doi.org/10.1007/s10534-004-1228-6
Issue Date:
DOI: https://doi.org/10.1007/s10534-004-1228-6