Influences of Peroxidase on Lysozyme Activity

Abstract

It is well known that many antimicrobial proteins in saliva interact with each other. The purpose of the present study was to investigate the interactions of lysozyme with peroxidase in the aspects of enzymatic activity in vitro. The interactions of lysozyme with peroxidase were examined by incubating hen egg-white lysozyme (HEWL) with bovine lactoperoxidase (bLP). The influence of peroxidase system on lysozyme was examined by subsequent addition of potassium thiocyanate and hydrogen peroxide. Lysozyme activity was determined by turbidity measurement of a Micrococcus lysodeikticus substrate suspension. Peroxidase activity was determined with an NbsSCN assay. The Wilcoxon signed rank test was used to analyze the changes of enzymatic activities compared with their controls. bLP at physiological concentrations enhanced the enzymatic activity of HEWL (P ＜ 0.05) and its effect was dependent on the concentration of peroxidase. However, HEWL did not affect the enzymatic activity of bLP. Thiocyanate did not affect the enzymatic activity of HEWL, either. The addition of potassium thiocyanate and hydrogen peroxide did not lead to additional enhancement of the enzymatic activity of HEWL. The changes of hydrogen peroxide concentration in the peroxidase system did not affect the enzymatic activity of HEWL. Collectively, despite an in vitro nature of our study, the results of the present study provide valuable information on the interactions of lysozyme and peroxidase in the aspects of enzymatic activity in oral health care products and possibly in the oral cavity. 타액에 존재하는 여러 항균물질은 상호작용을 통하여 부가적이거나 상승작용을 나타내고 때로는 저해작용을 나타내는 것으로 알려져 있다. 본 연구는 in vitro 상에서 lysozyme과 peroxidase 사이의 상호작용을 효소활성 측면에서 조사하고자 시행되었다. Lysozyme과 peroxidase의 상호작용은 hen egg-white lysozyme (HEWL)과 bovine lactoperoxidase (bLP)를 혼합하는 방법으로 조사되었고, peroxidase system이 lysozyme에 미치는 영향은 potassium thiocyanate와 hydrogen peroxide를 추가적으로 첨가하는 방법으로 조사되었다. Lysozyme 활성은 Micrococcus lysodeikticus 기질용액의 혼탁도 변화를 측정하는 방법으로 측정되었고, peroxidase 활성은 NbsSCN 법으로 측정되었다. Wilcoxon signed rank 법을 이용하여 lysozyme과 peroxidase 효소활성 변화를 대조군과 비교하였다. 생리적 농도범위에서 bLP는 HEWL의 효소활성을 증가시켰으며 (P ＜ 0.05), 그 효과는 bLP의 농도증가에 따라 영향을 받았다. 하지만 HEWL는 bLP의 효소활성에 영향을 주지 못하였다. Thiocyanate는 HEWL의 효소활성에 영향을 주지 못하였고, potassium thiocyanate와 hydrogen peroxide를 추가한 peroxidase system도 HEWL 효소활성의 추가적인 상승을 유도하지는 못하였으며, hydrogen peroxide의 농도변화도 영향을 미치지 못하였다. 본 연구의 결과는 타액 항균물질을 포함하고 있는 구강건강용품이나 구강에서 lysozyme과 peroxidase의 상호작용을 이해하는데 필요한 중요한 정보를 제공해준다.