HYPO-THIOCYANITE ION - INHIBITOR FORMED BY SYSTEM LACTOPEROXIDASE-THIOCYANATE-HYDROGEN PEROXIDE .1. IDENTIFICATION OF INHIBITING COMPOUND
HYPO-THIOCYANITE ION - INHIBITOR FORMED BY SYSTEM LACTOPEROXIDASE-THIOCYANATE-HYDROGEN PEROXIDE .1. IDENTIFICATION OF INHIBITING COMPOUND
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DOI：
10.1159/000260252
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发表时间：
1977-01-01
期刊：
影响因子：
4.2
通讯作者：
STODDARD, LA
中科院分区：
文献类型：
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作者：
HOOGENDOORN, H;PIESSENS, JP;STODDARD, LA
乳酸过氧化物酶（LPO）催化H2O2氧化SCN-的第一步导致形成OSCN-，即次硫氰酸离子。在稀非酸溶液中，该化合物比以前的研究表明的要稳定得多。以硫氰原（SCN）2为原料，在强碱性溶液中水解制备OSCN-。与LPO制剂一样，这些溶液对细菌（变形链球菌）具有抑制作用。OSCN-氧化巯基，在这个反应中，SCN-被再生。由于LPO系统的抑制作用显然是由于含有必需巯基的酶的氧化，因此OSCN-可能与抑制剂相同。总的机制可以通过干扰细胞的NADH-NADPH平衡来解释。在LPO的存在下，NADH的氧化产生H2O2，通过OSCN-氧化硫醇。对于它们的还原，同样需要NADPH。[这可能是唾液中存在的抑制牙菌斑细菌生长和酸形成的机制]。
The initial step in the lactoperoxidase (LPO) catalyzed oxidation of SCN- by H2O2 leads to the formation of OSCN-, the ion of hypothiocyanous acid. In dilute non-acid solutions, the compound is much more stable than previous investigations suggested. OSCN- was prepared non-enzymatically, by the hydrolysis of thiocyanogen (SCN)2 in strongly alkaline solution. These solutions were inhibitory towards bacteria [Streptococcus mutans], in the same way as the LPO preparations. OSCN- oxidizes thiol groups, and during this reaction SCN- is regenerated. Since the inhibitory effect of the LPO system is apparently due to the oxidation of enzymes containing essential thiol groups, OSCN- may be identical to the inhibitor. The over-all mechanism can be explained by an interference in the NADH-NADPH balance of the cell. In the presence of LPO the oxidation of NADH, giving H2O2, results via OSCN- in the oxidation of thiols. For their reduction, again, NADPH is required. [This may be the mechanism present in saliva which inhibits growth and acid formation of bacteria responsible for dental plaque.].