Patent ID: 7566529

Claim:
Method of recovering a retroviral reverse transcriptase (RT) activity from enveloped retroviruses in a biological sample containing non-protected cellular polymerases, comprising the steps of a) incubating the biological sample with a cysteine-modifying agent selected from the group consisting of N-ethylmalemide, Thimerosal, p-hydroxymercuribenzoate, 5,5′-dithiobis-(2-nitrobenzoic acid), 2-aminoethyl 2′-aminoethanethiolsulfonate, 2-nitro-5-thiocyanobenzoic acid, methyl methane-thiosulfonate, phenylmercuric acetate and 2,2′-dithiodipyridine, to destroy the activity of contaminating cellular polymerases while preserving retroviral RT activity within the virus envelope, b1) removing the enveloped virus particles from the incubation mixture using a virus binding matrix and a washing step, or b2) inactivating the cysteine-modifying agent with an inactivating substance while preserving the virus envelope from lysis, c) lysing the virus envelope with a lysing buffer to release the virus enzymes, and d) recovering the released retroviral RT enzyme from the lysing buffer.