| pyrimidine transferase | <enzyme> An enzyme catalyzing transfer of a pyridine or other bases into the position of the pyrimidine in thiamin; e.g., thiamin reacting with pyridine produces heteropyrithiamin and 4-methyl-5-(2'-hydroxyethyl)-thiazole. Synonym: pyrimidine transferase, thiaminase I. (05 Mar 2000) |
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| pyrimidine(6-4)pyrimidone photolyase | <enzyme> Catalyses the light-dependent repair of pyrimidine(6-4)pyrimidone photoproducts; shows 20-22% sequence identity with class I cpd photolyase; genbank d83701 (drosophila), d83702 (human) Registry number: EC 4.1.99.- Synonym: (6-4)photolyase (26 Jun 1999) |
| pyrimidine-5'-nucleotide nucleosidase | <enzyme> Also acts on some deoxyribonucleotides Registry number: EC 3.2.2.10 Synonym: pyr-5'-nt-nucleosidase (26 Jun 1999) |
| pyrimidine-guanine sequence-specific ribonuclease | <enzyme> From yolk granules of adult rana catesbeiana oocytes Registry number: EC 3.1.27.- Synonym: rc-rnase, rana catesbeiana rnase (26 Jun 1999) |
| pyrimidine-nucleoside phosphorylase | <enzyme> Consider uridine phosphorylase and thymidine phosphorylase Registry number: EC 2.4.2.2 Synonym: pyrimidine nucleoside phosphorylase (26 Jun 1999) |
| pyrimidodiazepine synthase | <enzyme> Converts pyruvoyl-h4-pterin to pyrimidodiazepine by removal of a methyl group and reduction of a ketone group; requires glutathione Registry number: EC 1.2.4.- Synonym: pda synthase (26 Jun 1999) |
| pyritaceous | <chemical> Of or pertaining to pyrites. See Pyritic. Source: Websters Dictionary (01 Mar 1998) |
| pyrite | <chemistry> A name given to a number of common sulphur-containing metallic minerals, sulphides of iron, copper, cobalt, nickel, and tin, of a white or yellowish colour. The term was originally applied to the mineral pyrite, or iron pyrites, in allusion to its giving sparks when struck with steel. Arsenical pyrites, arsenopyrite. Auriferous pyrites. See Auriferous. Capillary pyrites, millerite. Common pyrites, isometric iron disulphide; pyrite. Hair pyrites, millerite. Iron pyrites. Magnetic pyrites, pyrrhotite. Tin pyrites, stannite. White iron pyrites, orthorhombic iron disulphide; marcasite. This includes cockscomb pyrites (a variety of marcasite, named in allusion to its form), spear pyrites, etc. Yellow, or Copper, pyrites, the sulphide of copper and iron; chalcopyrite. Origin: L, fr. Gr, fr. Fire. See Pyre. Source: Websters Dictionary (01 Mar 1998) |
| pyrithiamin | A thiamin antimetabolite, differing from thiamin in that the thiazole ring of the thiamin molecule is replaced by a pyridine ring. Synonym: neopyrithiamin. (05 Mar 2000) |
| pyrithiamine | <chemical> A thiamine antagonist due to its inhibition of thiamine pyrophosphorylation. It is used to produce thiamine deficiency. Pharmacological action: antimetabolites. Chemical name: Pyridinium, 1-((4-amino-2-methyl-5-pyrimidinyl)methyl)-3-(2-hydroxyethyl)-2-methyl-, bromide, monohydrobromide (12 Dec 1998) |
| pyrithioxin | <chemical> 3,3'-(dithiodimethylene)bis[5-hydroxy-6-methyl-4-pyridinemethanol. Neurotropic agent. Reduces permeability of blood-brain barrier to phosphate. Has no vitamin b6 activity. Synonym: bonifen; encephabol Chemical name: 4-Pyridinemethanol, 3,3'-(dithiobis(methylene))bis(5-hydroxy-6-methyl- (12 Dec 1998) |
| pyritical | <chemistry> Of or pertaining to pyrites; consisting of, or resembling, pyrites. Source: Websters Dictionary (01 Mar 1998) |
| pyritiferous | <chemistry> Containing or producing pyrites. Source: Websters Dictionary (01 Mar 1998) |
| pyritohedral | <chemistry> Like pyrites in hemihedral form. See: Pyritohedron. Source: Websters Dictionary (01 Mar 1998) |
| pyritohedron | <chemistry> The pentagonal dodecahedron, a common form of pyrite. Origin: Pyrite + Gr. Base. Source: Websters Dictionary (01 Mar 1998) |