Yu X, Loimaranta V, Lenander-Lumikari M, Wunder D, Bowen W H, Tenuvuo J
Department of Stomatology, 1st Clinical College, Harbin Medical University, No. 23, Youzheng Street, Nangang District, Harbin-150001, Heilongjiang Province, P. R. China.
Chin J Dent Res. 2000 Aug;3(2):61-4.
To investigate the effects of the peroxidase system (LP, H2O2, SCN) and its components on the activity of glucosyltransferase D (GtfD) originating from Streptococcus mutans (S. mutans).
GtfD was incubated in buffered-KCl assay mixture that contained 20 microM dextran and 100 mM sucrose including 14C-glucose. The activity of GtfD was measured with a scintillation counter. The effects of lactoperoxidase system and its components on GtfD activity were examined by incubating different components separately and together with GtfD.
The lactoperoxidase system-generated hypothiocyanite (OSCN) had no effect on the activity of streptococcal GtfD, while the lactoperoxidase enzyme inhibited GtfD. The ratio between the 2 enzymes, LP and GtfD, was important for the inhibition. However, if LP was combined with its substrates, SCN and/or a high concentration of H2O2, it enhanced the activity of GtfD.
Peroxidase-generated antimicrobial agent HOSCN/OSCN is not inhibitory against GtfD, whereas low concentrations of the LP-enzyme inhibit GtfD.
研究过氧化物酶系统（乳过氧化物酶、过氧化氢、硫氰酸盐）及其各成分对变形链球菌葡糖基转移酶D（GtfD）活性的影响。
将GtfD在含有20微摩尔葡聚糖和100毫摩尔蔗糖（含14C-葡萄糖）的缓冲氯化钾测定混合物中孵育。用闪烁计数器测量GtfD的活性。通过将不同成分分别与GtfD一起孵育，研究乳过氧化物酶系统及其成分对GtfD活性的影响。
乳过氧化物酶系统产生的次硫氰酸盐（OSCN）对链球菌GtfD的活性无影响，而乳过氧化物酶抑制GtfD。两种酶（乳过氧化物酶和GtfD）的比例对抑制作用很重要。然而，如果乳过氧化物酶与其底物硫氰酸盐和/或高浓度过氧化氢结合，则会增强GtfD的活性。
过氧化物酶产生的抗菌剂HOSCN/OSCN对GtfD无抑制作用，而低浓度的乳过氧化物酶抑制GtfD。
