the gag and pol genes of the human immunodeficiency virus type 1 ( hiv-1 ) ( ref . 1 ) are translated as two polyproteins , pr55gag and pr160gag-pol ( refs 2-6 ) , which are subsequently cleaved by the action of a virus-encoded protease into the four structural gag proteins of the virion core ( p17 , p24 , p7 and p6 ) and the pol-encoded enzymes essential for retrovirus replication ( protease , reverse transcriptase , ribonuclease h , and endonuclease ) .
C0014442
enzymes
C0030946
protease