| homoserine deaminase | <enzyme> A multifunctional pyridoxal phosphate enzyme. In the final step in the biosynthesis of cysteine it catalyses the cleavage of cystathionine to yield cysteine, ammonia, and 2-ketobutyrate. Chemical name: L-Cystathionine cysteine-lyase (deaminating) Registry number: EC 4.4.1.1 (12 Dec 1998) |
|---|---|
| homoserine dehydratase | <enzyme> A multifunctional pyridoxal phosphate enzyme. In the final step in the biosynthesis of cysteine it catalyses the cleavage of cystathionine to yield cysteine, ammonia, and 2-ketobutyrate. Chemical name: L-Cystathionine cysteine-lyase (deaminating) Registry number: EC 4.4.1.1 (12 Dec 1998) |
| homoserine dehydrogenase | <enzyme> An enzyme that catalyses the reduction of aspartic beta-saemialdehyde to homoserine, which is the branch point in biosynthesis of methionine, lysine, threonine and leucine from aspartic acid. Chemical name: L-Homoserine:NAD(P)+ oxidoreductase Registry number: EC 1.1.1.3 (12 Dec 1998) |
| homoserine lactone | The cyclic ester (i.e., the d-lactone) of homoserine; formed by the reaction of cyanogen bromide on methionyl residues in peptides and proteins. (05 Mar 2000) |
| homosexual | A person sexually attracted to persons of the same sex. Homosexuals include males (gays) and females (lesbians). Homosexual can also be an adjective. (12 Dec 1998) |
| homosexuality | Sexuality directed toward someone of the same sex. (12 Dec 1998) |
| homosexuality, female | Sexual attraction or relationship between females. (12 Dec 1998) |
| homosexuality, male | Sexual attraction or relationship between males. (12 Dec 1998) |
| homospermidine synthetase | <enzyme> Proposed mechanism-schiff base formed between putrescine and its oxidation product, 4-aminobutyraldehyde, then reduced to sym-homospermidine; requires nad Registry number: EC 2.5.1.- Synonym: homospermidine synthase (26 Jun 1999) |
| homosporous | Producing only one kind of spore in the sexual reproductive cycle, and hence one gametophyte which produces both male and female gametes. Compare: heterosporous. (09 Oct 1997) |
| homosteroid | A steroid that has had at least one of the rings in its structure expanded. (05 Mar 2000) |
| homosteroids | Steroids whose structure has been expanded by the addition of one or more carbon atoms to the ring skeleton in any of the four rings. (12 Dec 1998) |
| homostyled | <botany> Having only one form of pistils; said of the flowers of some plants. Origin: Homo- + style. Source: Websters Dictionary (01 Mar 1998) |
| homostylous | Species in which the flowers have stigmas and anthers held at the same level relative to each other on all plants. Compare: heterostylous. (09 Oct 1997) |
| homosystemic | <biology> Developing, in the case of multicellular organisms, from the same embryonic systems into which the secondary unit (gastrula or plant enbryo) differentiates. Origin: Homo- + systemic. Source: Websters Dictionary (01 Mar 1998) |