Biochemical heterogeneity of reverse transcriptase purified from the AIDS virus, HTLV-III.
The reverse transcriptase from AIDS virus, HTLV-III, was purified and characterized. The purified enzyme has a very high affinity for template primers (rC)n X (dG)12 and (rCm)n X (dG)12 compared to that for (rA)n X (dT)12. In addition, the HTLV-III reverse transcriptase was able to transcribe (rAm)n X (dT)12 very efficiently. The ionic requirements are unique in the sense that HTLV-III reverse transcriptase prefers Mg2+ as divalent ions to transcribe (rC)n X (dG)12 and (rA)n X (dT)12. The Mr of the enzyme is 95 000-98 000. Unlike the HTLV-I reverse transcriptase, the HTLV-III enzyme is highly stable and has a much higher activity in the presence of (rC)n X (dG)12; the Vmax for HTLV-III reverse transcriptase is several-fold higher than that for HTLV-I enzyme. The enzyme activity of the purified reverse transcriptase from HTLV-III was resolved into two peaks on a preparative isoelectric column, one at pH 5.75 and the other at pH 6.25. This leads us to conclude that the reverse transcriptase of HTLV-III is biochemically heterogeneous.
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D002413:Cations, Divalent; D017977:Deltaretrovirus / Q000201:enzymology*; D007525:Isoelectric Focusing; D008274:Magnesium / Q000494:pharmacology; D008970:Molecular Weight; D012367:RNA, Viral / Q000378:metabolism; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism*; D013379:Substrate Specificity; D013698:Templates, Genetic
D002413:Cations, Divalent; D012367:RNA, Viral; D012194:RNA-Directed DNA Polymerase; D008274:Magnesium