| poly(A) | 1. <abbreviation> Poly(adenylic acid). 2. Iridoid indole alkaloid isolated from Vinca sp.; may have pharmacological applications; falling in this class are vinblastine and vincristine. 3. Excretion of d-glyceric acid in the urine; found in renal calculi. 4. An inborn error in metabolism resulting in d-glyceric aciduria. 5. A class of basic antibiotic peptides, found in neutrophils, that apparently kill bacteria by causing membrane damage. (05 Mar 2000) |
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| poly adenosine diphosphate ribose | <chemical> A polynucleotide formed from NAD in the presence of NAD+ nucleosidase. Chemical name: Adenosine 5'-(trihydrogen diphosphate), P'-5-ester with D-ribose, homopolymer (12 Dec 1998) |
| poly ADP-ribose glycohydrolase | <enzyme> Splits ribose-ribose bonds; glycohydrolase I has a higher molecular weight and is tightly bound to mammalian cell nuclei; glycohydrolase II has lower molecular weight and is found in cytosol Registry number: EC 3.2.1.- Synonym: (ADP-ribose)n glycohydrolase I, (ADP-ribose)n glycohydrolase II (26 Jun 1999) |
| poly A hydrolase | <enzyme> Endoribonuclease and exoribonuclease isolated; specific to poly(a) Registry number: EC 3.1.4.- Synonym: polyadenylase, polyadenylate hydrolase, poly a exonuclease (26 Jun 1999) |
| poly(A) polymerase | <enzyme> An enzyme that catalyses the formation of a poly(adenylic acid) sequence. (05 Mar 2000) |
| poly-a polymerase | <enzyme> An enzyme in the nucleus of acell that adds several adenine nucleotidesto the 3' end of a primarytranscript messenger RNA. (09 Oct 1997) |
| poly A specific exoribonuclease | <enzyme> Acts on 2' or 3'-linked oligoriboadenylates to liberate 5'-AMP Registry number: EC 3.1.13.- Synonym: 2',3'-exoribonuclease, 3'-exoribonuclease (26 Jun 1999) |
| poly(A)-specific ribonuclease | <enzyme> From vigna unguiculata seedlings; bifunctional enzyme responsible for both poly(a)-polymerizing and poly(a)-hydrolyzing activities; removes the poly(a) tail as the first step in degrading mRNA Registry number: EC 3.1.13.4 Synonym: poly(a) nuclease, mRNA poly(a) nuclease, poly(a) ribonuclease (pan), pan2 protein (26 Jun 1999) |
| poly A tail | <molecular biology> A sequence of adenine nucleotides that get added to the 3' end of some primary transcript messenger RNA molecules in eukaryotes during post-transcriptional processing. The added tail is believed to confer stability to the molecule. Histone mRNA do not have poly A tail. The poly A tail is added post transcriptionally to the primary transcript as part of the nuclear processing of RNA yielding hnRNAs with 60-200 adenylate residues in the tail. In the cytoplasm the poly A tail on mRNAs is gradually reduced in length. The function of the poly A tail is not clear but it is the basis of a useful technique for the isolation of eukaryotic mRNAs. The technique uses an affinity column with oligo(u) or oligo(dT) immobilised on a solid support. If cytoplasmic RNA is applied to such a column, poly A rich RNA (mRNA) will be retained. (13 Nov 1997) |
| poly a-u | <chemical> A double-stranded polyribonucleotide comprising polyadenylic and polyuridylic acids and believed to be a stimulant of the immune system through induction of interferon. Pharmacological action: antiviral agents, interferon inducers. Chemical name: 5'-Adenylic acid, homopolymer, complex with 5'-uridylic acid homopolymer (1:1) (12 Dec 1998) |
| poly(beta-D-mannuronate) lyase | <enzyme> Amino acid sequence has been determined for sp1 and sp2 isoenzymes from midgut of wreath shell, turbo cornutus Registry number: EC 4.2.2.3 Synonym: poly(1,4-beta-d-mannuronide)lyase, alginate lyase I, alginate lyase, aly gene product, mannuronate lyase sp1, mannuronate lyase sp2 (26 Jun 1999) |
| poly-beta-glucosaminidase | <enzyme> An enzyme which breaks down chitin, which is a polysaccharide that forms the hard outer shell of arthropods (insects, spiders, crustaceans, etc.), and the cell walls of fungi, and some algae. (09 Oct 1997) |
| poly-beta-hydroxybutyrate | <biochemistry> A common storage material of prokaryotic cells consisting of a polymer of beta-hydroxybutyrate (PHB) or other beta-alkanoic acids (PHA). (09 Oct 1997) |
| poly-beta-hydroxybutyrate polymerase | <enzyme> 3rd enzyme of the poly-beta-hydroxybutyrate biosynthetic pathway in alcaligens eutrophus; acts via, an acyl s-enzyme intermediate Registry number: EC 2.3.1.- Synonym: phb polymerase, phb synthase, phac gene product, poly-beta-hydroxybutyrate synthetase (26 Jun 1999) |
| poly c | <chemical> A group of cytosine ribonucleotides in which the phosphate residues of each cytosine ribonucleotide act as bridges in forming diester linkages between the ribose moieties. Chemical name: 5'-Cytidylic acid, homopolymer (12 Dec 1998) |