RT Journal Article SR Electronic(1) A1 Schommer, Stefanie A1 Sauter, Marlies A1 Kräusslich, Hans-Georg A1 Best, Barbara A1 Mueller-Lantzsch, NikolausYR 1996 T1 Characterization of the human endogenous retrovirus K proteinase JF Journal of General Virology, VO 77 IS 2 SP 375 OP 379 DO https://doi.org/10.1099/0022-1317-77-2-375 PB Microbiology Society, SN 1465-2099, AB The proteinase of the human endogenous retrovirus K (HERV-K) shows similarity to retrovirus aspartic proteinases. It is translated from a transcript composed of gag and prt. The proteinase was expressed either as full-length native protein or as truncated protein in Escherichia coli. Functional protein was demonstrated by its autocatalytic cleavage into an 18 kDa fragment recognized by a polyclonal antiserum. This autocatalytic cleavage was specifically inhibited by a human immunodeficiency virus type 1 proteinase inhibitor. The HERV-K proteinase expressed in E. coli was capable of cleaving HERV-K Gag translated in vitro. Major protein fragments of 39 and 30 kDa, and minor protein fragments of 26, 22 and 21 kDa were obtained. Similar fragments are also observed in the human teratocarcinoma cell line Teral. Our data suggest that the HERV-K proteinase is functionally equivalent to other retrovirus proteinases and thus probably functions in the processing of Gag precursor protein., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-77-2-375