HIV reverse transcriptase (RNA-dependent DNA polymerase) is an enzyme that catalyzes the synthesis of DNA on an RNA matrix during reverse transcription. After the viral RNA enters the cell, the reverse transcriptase synthesizes complementary DNA and uses it to produce a second DNA chain.
HIV integrase is an enzyme that catalyzes the integration (inclusion) of viral DNA into the chromosome of a host cell. As a result, viral DNA is continuously present in a cell and provides the expression of viral genes.
HIV protease is an enzyme that cuts the synthesized polyproteins (in particular, Gag and Gag-Pol) in specific sites providing the production of mature HIV virion proteins. As a result, viral enzymes (reverse transcriptase, integrase, and protease), structural proteins (capsid and nucleocapsid), and other factors necessary for the life cycle of the virus are formed and are packed into new virions.