| ortho- | 1. <prefix> A combining form signifying straight, right, upright, correct, regular; as, orthodromy, orthodiagonal, orthodox, orthographic. 2. <chemistry> Connection with, or affinity to, one variety of isomerism, characteristic of the benzene compounds; contrasted with meta- or para-; as, the ortho position; hence, designating any substance showing such isomerism; as, an ortho compound. In the graphic representation of the benzene nucleus (see Benzene nucleus, under Benzene), provisionally adopted, any substance exhibiting double substitution in adjacent and contiguous carbon atoms, as 1 & 2, 3 & 4, 4 & 5, etc, is designated by ortho-; as, orthoxylene; any substance exhibiting substitution of two carbon atoms with one intervening, as 1 & 3, 2 & 4, 3 & 5, 4 & 6, etc, by meta-; as, resorcin or metaxylene; any substance exhibiting substitution in opposite parts, as 1 & 4, 2 & 5, 3 & 6, by para-; as, hydroquinone or paraxylene. Origin: Gr. Straight; akin to Skr. Rdhva upright, vrdh to grow, to cause to grow. (29 Oct 1998) |
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| ortho-halobenzoate 1,2-dioxygenase | <enzyme> A three-component broad substrate-specific enzyme that requires oxygen, NADH, fe(ii) and flavin adenine dinucleotide; degrades 2,4-, 2,5-dichloro-, 2-chloro (& a variety of other substituted halobenzoates) to 4-chlorocatechol and catechol Registry number: EC 1.14.12.- (26 Jun 1999) |
| toluene ortho-monooxygenase | <enzyme> Enzyme from pseudomonas sp. Strain js150 acts on both toluene and benzene; amino acid sequence has been determined; also hydroxylates cresol to 3-methylcatechol Registry number: EC 1.13.12.- Synonym: toluene 2-monooxygenase, toluene-benzene-2-monooxygenase (26 Jun 1999) |