Biology
- Q: Compare And Contrast Dna Replication And Transcription
Similarities: Both processes occur in the nucleus. Both processes also involve specific complementary base pairing. Both processes involving the unwinding of the double helix DNA. Both processes involve forming of hydrogen bonds between the original DNA...
- Dna Strands Separate At The Replication Fork
KEY TERMS:A replication fork (Growing point) is the point at which strands of parental duplex DNA are separated so that replication can proceed. A complex of proteins including DNA polymerase is found at the fork. A DNA polymerase is an enzyme that...
- Lipase
Term: lipaseLiterally meaning: ?the enzyme that breaks down lipids?Origin: Anc Greek+ ?????/?????(=fat, grease) >????? > verb ?????/livo(=grease)+(-???)/(-asy)(=-ase) enzyme suffix added to the name of the substrate that the enzyme hydrolyzes...
- Proteinase K
Term: proteinase (or endopeptidase K) Literally meaning: ?that enzyme which separates proteins?Origin: Anc Greek+????????/proteini(=protein) > ??????/protos(=first or of prime importance) +(-???)/(-asy)(=-ase) enzyme suffix added to the name of the...
- Elastase
Term: elastaseLiterally meaning: ?separating elastin?Origin: Anc Greek ????/elao(=be flexibe or ductile)) >??????/elavno(=run, drive)-???/-asy(=-ase) suffix added to the name of the substrate that the enzyme hydrolyzes eg proteinase for protein...
Biology
helicase
Term: helicase
Literally meaning: ?protein of unwinding helix?
Origin: Anc Greek
??????/elisso(=twist, turn) > ?å???/helix(=helix, something spiral)
+-???/-asy(=-ase) suffix added to the name of the substrate that the enzyme hydrolyzes eg proteinase for protein or lipase for lipids
>???-/dia-(=prefix denoting ?through?, ?apart? )
> ???/dio(two) + ??????/stasis(=halt) > ??????/histimi(=stand).
Coined/History
The discovery of first helicase was in 1976 in pocaryotic organism (Escherichia coli ) and two years later in an the eucaryotic lily . The enzymes were classified then as ?unwinding proteins? and first time as helicases in 1982 by Venkatesan et al. Since then a large number of these enzymes have been isolated from both procaryotic and eukaryotic systems, and the number is still growing.
Sources
1. Abdel-Monem, M., Durwald, H. & Ho?mann-Berling, H. (1976) Enzymic unwinding of DNA. II. Chain separation by an ATP-dependent DNA unwinding enzyme. Eur. J. Biochem. 65,441?449.
2. Hotta, Y. & Stern, H. (1978) DNA unwinding protein from meiotic cells of Lilium. Biochemistry 17, 1872?1880.
3. Venkatesan, M., Silver, I.L. & Nossal, N.G. (1982) Bacteriophage T4 gene 41 protein, required for the synthesis of RNA primers, is also a DNA helicase. J. Biol. Chem. 257, 12426?12434.
Definition
Helicases are a group of enzymes that, using ATP, move along a nucleic acid phopsphodiester backbone in order to unwind and separate two annealed nucleic acids strands. Helicases are essential in nucleic acid metabolism , including replication, repair, recombination, and transcription. at replication fork.
- Q: Compare And Contrast Dna Replication And Transcription
Similarities: Both processes occur in the nucleus. Both processes also involve specific complementary base pairing. Both processes involving the unwinding of the double helix DNA. Both processes involve forming of hydrogen bonds between the original DNA...
- Dna Strands Separate At The Replication Fork
KEY TERMS:A replication fork (Growing point) is the point at which strands of parental duplex DNA are separated so that replication can proceed. A complex of proteins including DNA polymerase is found at the fork. A DNA polymerase is an enzyme that...
- Lipase
Term: lipaseLiterally meaning: ?the enzyme that breaks down lipids?Origin: Anc Greek+ ?????/?????(=fat, grease) >????? > verb ?????/livo(=grease)+(-???)/(-asy)(=-ase) enzyme suffix added to the name of the substrate that the enzyme hydrolyzes...
- Proteinase K
Term: proteinase (or endopeptidase K) Literally meaning: ?that enzyme which separates proteins?Origin: Anc Greek+????????/proteini(=protein) > ??????/protos(=first or of prime importance) +(-???)/(-asy)(=-ase) enzyme suffix added to the name of the...
- Elastase
Term: elastaseLiterally meaning: ?separating elastin?Origin: Anc Greek ????/elao(=be flexibe or ductile)) >??????/elavno(=run, drive)-???/-asy(=-ase) suffix added to the name of the substrate that the enzyme hydrolyzes eg proteinase for protein...