| helix loop helix | <molecular biology> A motif associated with transcription factors, allowing them to recognise and bind to specific DNA sequences. Two _ helices are separated by a loop. Examples: myoblast MyoD1, c myc, Drosophila genes daughterless, hairy, twist, scute, achaete, asense. Not the same as helix turn helix. (18 Nov 1997) |
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| helix-loop-helix motifs | A group of 20-residue peptides characterised by two alpha helices separated by a non-helical segment. These recurring supersecondary structural patterns are found in many sequence-specific DNA-binding proteins. (12 Dec 1998) |
| helix turn helix | <molecular biology> A motif associated with transcription factors, allowing them to bind to and recognise specific DNA sequences. Two amphipathic _ helices are separated by a short sequence with a _ sheet. One helix lies across the major groove of the DNA, while the recognition helix enters the major groove and interacts with specific bases. An example in Drosophila is the homeotic gene fushi tarazu, that binds to the sequence TCAATTAAATGA. Not the same as helix loop helix. (18 Nov 1997) |
| helix-turn-helix motifs | The first DNA-binding protein motif to be recognised. Helix-turn-helix motifs were originally identified in bacterial proteins but have since been found in hundreds of DNA-binding proteins from both eukaryotes and prokaryotes. They are constructed from two alpha helices connected by a short extended chain of amino acids, which constitute the "turn." the two helices are held at a fixed angle, primarily through interactions between the two helices. (12 Dec 1998) |
| alpha helix | <molecular biology> A particular helical folding of the polypeptide backbone in protein molecules (both fibrous and globular), in which the carbonyl oxygens are all hydrogen bonded to amide nitrogen atoms three residues along the chain. The translation of amino acid residues along the long axis is 0.15 nm and the rotation per residue, 100 |
| alpha, alpha-phosphotrehalase | <enzyme> Forms glucose plus glucose-6-phosphate Registry number: EC 3.2.1.93 Synonym: trehalose-6-phosphate hydrolase, phospho-alpha(1,1)glucosidase, trea gene product, trec gene product (26 Jun 1999) |
| alpha,alpha-trehalose phosphorylase | <enzyme> Chemical name: alpha-d-glucopyranosyl-alpha-d-glucopyranose orthophosphate glucosyltransferase Registry number: EC 2.4.1.64 Synonym: trehalose phosphorylase (26 Jun 1999) |
| alpha-dextrin endo-1,6-alpha-glucosidase | <enzyme> An enzyme with action similar to that of isoamylase; it cleaves 1,6-alpha-glucosidic linkages in pullalan, amylopectin, and glycogen, and in alpha-and beta-amylase limit-dextrins of amylopectin and glycogen. Compare: isoamylase. Synonym: limit dextrinase, pullulanase, R enzyme. (05 Mar 2000) |
| alpha-hydroxymethyl-alpha'-(N-acetylaminomethylene)succinic acid hydrolase | <enzyme> Involved in degradation of vitamin b6; forms acetic acid plus ammonia plus carbon dioxide plus alpha-hydroxymethyl-succinic monoaldehyde Registry number: EC 3.5.1.- Synonym: compound b hydrolase (26 Jun 1999) |
| cholesterol-5 alpha,6 alpha-epoxide hydrase | <enzyme> Aspect of epoxide hydrolase, EC 3.3.2.3 Pharmacological action: carcinogen Registry number: EC 3.3.2.- Synonym: cholesterol epoxide hydrase, cholesterol epoxide hydrolase (26 Jun 1999) |
| CMP-acetylneuraminate-alpha-N-acetylneuramide alpha-2,8-sialyltransferase | <enzyme> Forms ganglioside gd3 Registry number: EC 2.4.99.8 Synonym: cmp-n-acetylneuraminate-gm3 sialyltransferase, gm3-sialosyltransferase, gd3 synthase, gd3-synthase, cmp-n-acetylneuraminate-(n-acetylneuraminyl)-d-galactosyl-d-glucosylceramide sialyltransferase, sialyltransferase II, st II, g(m3) alpha-2,8-sialyltransferase, st8sia I, stii enzyme, stiii enzyme, gt3 synthase (26 Jun 1999) |
| CMP-N-acetylneuraminate-alpha-N-acetylgalactosaminide alpha-2,6-sialyltransferase | <enzyme> Enzyme from foetal calf liver; forms branched tetrasaccharide, neuac-alpha2-3gal-beta1-3(neuac-alpha2-6)galnac of fetuin Registry number: EC 2.4.99.3 Synonym: cmp-aag-sialyltransferase, st6galnaci, galnac 2,6-sialyltransferase (26 Jun 1999) |
| NAD 3 alpha-hydroxy-5 alpha-pregnan-20-one-oxidoreductase | <enzyme> From rat liver microsomes Registry number: EC 1.1.1.- Synonym: nad-3-hp-20-oor (26 Jun 1999) |
| 1,4-alpha-d-glucan 6-alpha-d-glucosyltransferase | A glucosyltransferase that transfers an alpha-glucosyl residue in a 1,4-alpha-glucan to the primary hydroxyl group of glucose in a 1,4-alpha-glucan. See: 1,4-alpha-d-glucan branching enzyme. Synonym: oligoglucan-branching glycosyltransferase. (05 Mar 2000) |
| 1,4-alpha-glucan 6-alpha-glucosyltransferase | <enzyme> From aspergillus niger and oryzae Registry number: EC 2.4.1.24 (26 Jun 1999) |