Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.1.26.4 (
RNase H
)
2,751
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
A
ribonuclease H
which degrades RNA specifically in RNA-DNA hybrids and, moreover, stimulates its homologous DNA-polymerase-primase complex was purified from calf thymus. The enzyme consists of a single polypeptide of molecular mass
78 kDa
. It requires divalent cations for activity, and prefers Mg2+ over Mn2+. Ribonuclease H is optimally active at neutral pH and in 75 mM potassium acetate and is strongly sensitive to N-ethylmaleimide. [3H]Poly(rA).poly(dT), [3H]poly(rC).poly(dI), and [3H]RNA.M13-DNA are degraded to 3-9-mer oligoribonucleotides with similar kinetics, whereas double- or single-stranded DNA, and double- and single-stranded RNA remain unaffected. The enzyme stimulates in vitro DNA synthesis by the immunoaffinity-purified calf-thymus DNA-polymerase-alpha-primase complex threefold. When
ribonuclease H
is present in a three-fold molar excess to the polymerase-primase complex, twice as much primer is formed as in the absence of
ribonuclease H
. Ribonuclease H also stimulates the elongation rate of DNA polymerase alpha by a factor of 2-3, independent of whether primase-primed DNA templates or templates primed with oligonucleotides are used. Our results suggest that this form of
ribonuclease H
is a likely candidate for a genuine primer-removing enzyme in mammalian cells.
...
PMID:A distinct form of ribonuclease H from calf thymus stimulates its homologous DNA-polymerase-alpha-primase complex. 255 72
