Enzymes
| UniProtKB help_outline | 273 proteins |
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- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,176 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O2 Identifier CHEBI:16240 (Beilstein: 3587191; CAS: 7722-84-1) help_outline Charge 0 Formula H2O2 InChIKeyhelp_outline MHAJPDPJQMAIIY-UHFFFAOYSA-N SMILEShelp_outline [H]OO[H] 2D coordinates Mol file for the small molecule Search links Involved in 426 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline thiocyanate Identifier CHEBI:18022 (Beilstein: 1901207; CAS: 302-04-5) help_outline Charge -1 Formula CNS InChIKeyhelp_outline ZMZDMBWJUHKJPS-UHFFFAOYSA-M SMILEShelp_outline [S-]C#N 2D coordinates Mol file for the small molecule Search links Involved in 7 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,048 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline hypothiocyanous acid Identifier CHEBI:133907 (CAS: 63296-34-4) help_outline Charge 0 Formula CHNOS InChIKeyhelp_outline ZCZCOXLLICTZAH-UHFFFAOYSA-N SMILEShelp_outline C(#N)SO 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:69416 | RHEA:69417 | RHEA:69418 | RHEA:69419 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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The inhibition of streptococci by lactoperoxidase, thiocyanate and hydrogen peroxide. The oxidation of thiocyanate and the nature of the inhibitory compound.
Oram J.D., Reiter B.
1. The products of the lactoperoxidase-catalysed oxidation of thiocyanate by hydrogen peroxide were sulphate, carbon dioxide and ammonia. Cyanate, sulphite and a compound showing increased extinction at 235mmu (the ;235 compound') were intermediate oxidation products. 2. Two of the intermediates a ... >> More
1. The products of the lactoperoxidase-catalysed oxidation of thiocyanate by hydrogen peroxide were sulphate, carbon dioxide and ammonia. Cyanate, sulphite and a compound showing increased extinction at 235mmu (the ;235 compound') were intermediate oxidation products. 2. Two of the intermediates acted as electron acceptors in the oxidation of NADH(2). Thus NADH(2) was oxidized by sulphite in the presence of lactoperoxidase (EC 1.11.1.7) and Mn(2+) and by the ;235 compound' in the presence of an enzyme, the NADH(2)-oxidizing enzyme, present in extracts of lactoperoxidase-resistant streptococci. Sulphur dicyanide also acted as an electron acceptor in the latter reaction. The ;235 compound' was also reduced non-enzymically by sulphite. 3. The glycolysis of lactoperoxidasesensitive streptococci suspended in glucose solution was not inhibited by sulphite, cyanate, cyanide or the ;235 compound' but was inhibited by sulphur dicyanide. The inhibition by 0.1mm-sulphur dicyanide could be reversed, as could that caused by lactoperoxidase, thiocyanate and hydrogen peroxide, by washing the cells or by the addition of a cell-free extract of a lactoperoxidase-resistant streptococcus. 4. The effects of 0.1mm-sulphur dicyanide on catabolic enzymes of resting streptococci were very similar to those of the lactoperoxidase-thiocyanate-hydrogen peroxide system. Thus hexokinase was completedly inhibited, glucose 6-phosphate dehydrogenase and aldolase were partially inhibited and phosphohexokinase was little affected in both cases. << Less
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Hypothiocyanite ion; the inhibitor formed by the system lactoperoxidase-thiocyanate-hydrogen peroxide. I. Identification of the inhibiting compound.
Hoogendoorn H., Piessens J.P., Scholtes W., Stoddard L.A.
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Structural evidence of substrate specificity in mammalian peroxidases: structure of the thiocyanate complex with lactoperoxidase and its interactions at 2.4 A resolution.
Sheikh I.A., Singh A.K., Singh N., Sinha M., Singh S.B., Bhushan A., Kaur P., Srinivasan A., Sharma S., Singh T.P.
The crystal structure of the complex of lactoperoxidase (LPO) with its physiological substrate thiocyanate (SCN(-)) has been determined at 2.4A resolution. It revealed that the SCN(-) ion is bound to LPO in the distal heme cavity. The observed orientation of the SCN(-) ion shows that the sulfur at ... >> More
The crystal structure of the complex of lactoperoxidase (LPO) with its physiological substrate thiocyanate (SCN(-)) has been determined at 2.4A resolution. It revealed that the SCN(-) ion is bound to LPO in the distal heme cavity. The observed orientation of the SCN(-) ion shows that the sulfur atom is closer to the heme iron than the nitrogen atom. The nitrogen atom of SCN(-) forms a hydrogen bond with a water (Wat) molecule at position 6'. This water molecule is stabilized by two hydrogen bonds with Gln(423) N(epsilon2) and Phe(422) oxygen. In contrast, the placement of the SCN(-) ion in the structure of myeloperoxidase (MPO) occurs with an opposite orientation, in which the nitrogen atom is closer to the heme iron than the sulfur atom. The site corresponding to the positions of Gln(423), Phe(422) oxygen, and Wat(6)' in LPO is occupied primarily by the side chain of Phe(407) in MPO due to an entirely different conformation of the loop corresponding to the segment Arg(418)-Phe(431) of LPO. This arrangement in MPO does not favor a similar orientation of the SCN(-) ion. The orientation of the catalytic product OSCN(-) as reported in the structure of LPO.OSCN(-) is similar to the orientation of SCN(-) in the structure of LPO.SCN(-). Similarly, in the structure of LPO.SCN(-).CN(-), in which CN(-) binds at Wat(1), the position and orientation of the SCN(-) ion are also identical to that observed in the structure of LPO.SCN. << Less
J. Biol. Chem. 284:14849-14856(2009) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.