HIV-1, like other retroviruses, expresses its protein genes by first generating a polyprotein, consisting of head-to-tail assembly of all (or nearly all) HIV-1 proteins. These polyproteins must undergo proteolysis at specific sites to generate the individual proteins that are used in HIV replication, packaging, and egress from infected cells.
HIV protease activity

HIV protease cleaves polypeptide precursors into individual functional proteins. (Kuriyan et al, 2008)

All known retroviruses encode a protease that performs this function, and HIV-1 protease specifically chops up the HIV-1 polyprotein into virus-specific functional proteins (Dunn et al., 2002).


Dunn, Goodenow, Gustchina & Wlodawer. 2002. Genome Biology. Protein Family Review: Retroviral proteases.

Kuriyan, Konforti & Wemmer. 2008. The Molecules of Life: Physical and Chemical Principles.