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)
The active sites in reverse transcriptase of avian myeloblastosis virus have been selectively modified by various chemical reagents. The DNA polymerase activity is very sensitive to hydrophobic sulfhydryl reagents such as 5,5'-dithiobis(2-nitrobenzoic acid) and p-hydroxymercuribenzoate but resistant to sulfhydryl reagents with hydrophilic properties. The
RNase H
activity, on the other hand, is resistant to both hydrophobic and hydrophilic sulfhydryl reagents, indicating the absence of cysteinyl residues essential for
RNase H
activity.
N-Ethylmaleimide
(
NEM
), an amino and sulfhydryl group specific reagent, inactivates both DNA polymerase and
RNase H
, the later activity being fourfold more stable. Polynucleotides, but not nucleotide triphosphates, protect the two enzymatic activites of reverse transcriptase against
NEM
. Since pretreatment of the enzyme with 5,5' -dithiobis(2-nitrobenzoic acid) does not prevent N-ethylmaleimide from reacting with a residue necessary for DNA polymerase activity, two different reactive groups are probably involved with this enzymatic activity. The pH profile of reverse transcriptase inhibition by N-ethylmaleimide also suggests the involvement of two reactive groups essential for the DNA polymerase activity with apparent pKas of 5.5 and 6.5. Only one reactive group with a pKa of 7.5 is found associated with the
RNase H
activity.
...
PMID:Discrimination of DNA polymerase and RNase H activities in reverse transcriptase of avian myeloblastosis virus. 7 19
