<p class="p1">One of the first AIDS therapeutics were nucleotide or nucleoside analogues (NRTI – nucleoside-analogue reverse transcriptase inhibitors) – pseudosubstrates, that are during reverse transcription integrated into viral DNA instead of nucleosides and thus block the transcription. These drugs were superseded by non-nucleoside inhibitors (NNRTI) that could inhibit reverse transcriptase by binding into the alosteric site of the enzyme. The third type of drugs is a family of HIV protease inhibitors. In most cases specific inhibitors are very similar to protease substrates - the only difference is that because they cannot be cut, they block the active site by remaining bound into it.</p>