Protease inhibitor refers to a substance that binds to some groups on the active center of a protease molecule in a broad sense, and the protease activity is decreased or even disappeared, but the enzyme protein is not denatured.
Protease is a specific asparaginase encoded by the human immunodeficiency virus gene. Its function is to cleave the protein produced by gene and gene expression into active viral structural proteins and enzymes, which are key substances for HIV virus replication. Protease inhibitors are a chemically similar drug for the treatment of AIDS. Protease inhibitors are peptide compounds, which are important components of anti-HIV drug combination therapy. They are new products in the mid-to-late 1990s. The drug synthesis process is difficult, and it is also the main reason for the high cost of anti-HIV treatment. It is called " Must cross the barrier." Protease inhibitors are mainly: nelfinavir, saquinavir, indinavir, amprenavir, ritonavir and combination preparations.
Nefenavir is used in patients with acquired immunodeficiency syndrome (AIDS) and HIV-1 infection. This product is a non-peptide HIV protease inhibitor that binds reversibly to the active site of HIV protease to prevent HIV protease and affect the terminal formation of the virus.
Figure 1. Chemical structure of Nefenavir.
Saquinavir is an antiretroviral drug that is used in combination with other drugs to treat or prevent HIV/AIDS. Typically, it is used with ritonavir or lopinavir/ritonavir to enhance its effects. Side effects of saquinavir include nausea, vomiting, diarrhea and feeling tired. More serious side effects include QT prolongation, heart block, hyperlipidemia and liver problems. It seems to be safe during pregnancy. It belongs to the class of protease inhibitors and acts by blocking HIV protease.
Figure 2. Chemical structure of saquinavir.
Indinavir is used for HIV-I infection in adults. It can be used in combination with antiretroviral preparations (eg, nucleoside and non-nucleoside reverse transcriptase inhibitors) to treat HIV-I infection in adults. Adult patients who are clinically unsuitable for treatment with nucleoside or non-nucleoside reverse transcriptase inhibitors are used alone.
Figure 3. Chemical structure of indinavir.
Amprenavir is a new anti-reverse virus protease inhibitor with anti-HIV-1 and HIV-2 proteases that block the protein precursors necessary for HIV maturation, interfere with the growth of the virus, and then release Immature, non-infectious viral molecules. Long-term application of this product can usually reduce the HIV viral load in the blood, increase the count of CD4 cells, reduce the chance of contracting AIDS, improve the quality of life, and prolong life.
Figure 4. Chemical structure of Amprenavir.
Ritonavir is an orally effective inhibitor of human immunodeficiency virus-1 (HIV-1) and human immunodeficiency virus-2 (HIV-2) aspartic protease, blocking the enzyme to promote the production of morphologically mature HIV particles The desired polyprotein keeps the HIV particles in an immature state, thereby slowing the spread of HIV in the cells to prevent a new round of infection and delay the progression of the disease. Ritonavir is generally effective in aligning with dovudine-sensitive and zidovudine-resistant saquinavir-resistant HIV strains.
Figure 5. Chemical structure of Ritonavir.
Protease inhibitors are peptide-based compounds that either competitively inhibit protease activity or act as inhibitors of complementary protease activity sites. These drugs inhibit the activity of proteases, which are mainly used in the final stage of HIV replication. Since proteases are inhibited, DNA formed from infected CD4 nuclei cannot aggregate and release. A precursor protein encoded by a retroviral gene such as HIV needs to be cleaved into a functional structural protein by a protease to assemble into a complete virus particle. Protease inhibitors can bind to viral proteases to inhibit gene activity, resulting in protein precursors that cannot cleave and form mature virions.
Scientists are investigating whether protease inhibitors are likely to be used to treat cancer. For example, nelfinavir and atazanavir are capable of killing tumor cells in a culture dish (in a culture dish). But studies in laboratory mice have shown that nelfinavir inhibits tumor growth in these animals, which represents a promising clue to testing the drug in humans. Proteasome inhibitors, such as bortezomib, are now first-line drugs for the treatment of multiple myeloma.
The researchers found that after taking the protease inhibitor for 3 months or more, some patients showed abnormal deposition of adipose tissue under the same weight, which was expressed as "buffalo back" (ie, adipose tissue at the base of the neck). Pot-shaped abdomen or "full moon face". Other patients have fat loss in their limbs or face after taking protease inhibitors. These symptoms are very common in patients with Cushing's syndrome. The syndrome was caused by an abnormal increase in serum corticosterone, but no evidence of elevated serum corticosterone was found in these patients. There are at least four protease inhibitors that cause abnormal deposition of fat: indinavir, nelfinavir, ritonavir, and saquinavir. Some studies have shown that protease inhibitors may affect metabolic function, causing elevated triglycerides and blood sugar, insulin resistance, and diabetes, but these abnormalities are not found in these patients with fat deposition. Similarly, it is unclear whether fat deposition is reversible after dressing change.
1. Rawlings ND.; et al. Evolutionary families of peptidase inhibitors. Biochem. J. 2004, 378 (Pt 3): 705–716.