Scientific Research and Essays

  • Abbreviation: Sci. Res. Essays
  • Language: English
  • ISSN: 1992-2248
  • DOI: 10.5897/SRE
  • Start Year: 2006
  • Published Articles: 2755

The effects of norepinephrine on lactoperoxidase enzyme (LPO)

Melda Sisecioglu1, Ilhami Gulcin1,2*, Murat Cankaya3, Ali Atasever1,4 and Hasan Ozdemir1
1Department of Chemistry, Faculty of Sciences, Atatürk University, 25240-Erzurum, Turkey. 2School of Health Services, Ibrahim Çeçen University, 04100-Agrı, Turkey. 3Department of Biology, Faculty of Sciences and Arts, Erzincan University, 24100-Erzincan, Turkey. 4Department of Food, Ispir Hamza Polat Vocational School, Atatürk University, 25900-Ispir, Erzurum, Turkey.
Email: [email protected], [email protected]

  •  Accepted: 19 May 2010
  •  Published: 04 June 2010


Norepinephrine, a hormone and a neurotransmitter, was known as catecholamine. In the present study, we examined the inhibitory effect of norepinephrine on lactoperoxidase enzyme purified from bovine milk. Lactoperoxidase (LPO; E.C. was purified from bovine milk with three purification steps: Amberlite CG-50 resin, CM-Sephadex C-50 ion-exchange chromatography and Sephadex G-100 gel filtration chromatography, respectively. LPO was purified with a yield of 31.5%, a specific activity of 30.33 EU/mg proteins and 20.77 purification fold. To determine enzyme purity, SDS-PAGE was performed and single band was observed. The Rz (A412/A280) value for LPO was 0.9. The effect of norepinephrine on lactoperoxidase was determined using ABTS as a chromogenic substrate. The half maximal inhibitory concentration (IC50) value norepinephrine was found to be 67.2 µM. Also, inhibition constant (Ki) for norepinephrine was found to be 62.0 µM. Norepinephrine was found as non-competitive inhibitor.


Key words: Noradrenaline, norepinephrine, lactoperoxidase, LPO, enzyme purification, inhibition.