What is NS3/4A protease inhibitor?
NS3/4A protease has a crucial role in the replication cycle of hepatitis C virus. It cleaves polyprotein in four sequential active sites, forming the N-terminal proteins NS4A, NS4B, NS5A and NS5B. Regarding its chemical properties, this enzyme is related to the serine protease group.
What does NS3 protease do?
Introduction. The NS3/4A protease is responsible for selective cleavage of polyproteins into individual viral proteins (NS4A, NS4B, NS5A, and NS5B).
How do NS3/4A inhibitors work?
The NS3/4A protease interferes with the pathogen recognition TLR3- and RIG-I/MDA5-mediated signaling pathways, by cleaving TRIF and MAVS (also known as Cardif, VISA or IPS-1) signaling adaptors, respectively, preventing the transcriptional activation of type I interferon (IFN) genes and IFN-stimulated genes (ISGs) .
What is NS5A inhibitor?
Non-structural protein 5A (NS5A) inhibitors are a direct-acting antiviral agent used to treat hepatitis C virus (HCV). The NS5A protein has a substantial role in viral replication, packaging, assembly and complex interactions with cellular functions.
What are PI drugs?
Protease inhibitors (PIs) are antiviral drugs used for treating human immunodeficiency virus (HIV) infections and hepatitis C virus (HCV) infections. During infection with HIV or hepatitis C, the HIV or HCV multiply within the body’s cells.
What is NS5A and NS5B?
The hepatitis C virus (HCV) NS5B protein contains the RNA dependent RNA polymerase (RdRp) activity that catalyzes the synthesis of the viral genome with other host and viral factors. NS5A is an HCV-encoded protein previously shown to localize to the replisome and be necessary for viral replication.
What is a protease inhibitor and how does it work?
Protease inhibitors, which figure among the key drugs used to treat HIV, work by binding to proteolytic enzymes (proteases). That blocks their ability to function. Protease inhibitors don’t cure HIV. But by blocking proteases, they can stop HIV from reproducing itself.
How do direct acting antivirals work?
Since the start of this review, two other direct-acting antivirals, Epclusa (sofosbuvir / velpatasvir) and Zepatier (elbasvir / grazoprevir), have been authorised in the EU. Direct-acting antivirals work by blocking the action of proteins which are essential for making new hepatitis C viruses.
What are DAA drugs?
Direct-acting antivirals (DAA) are drugs used to treat hepatitis C infections. They are a combination of antiviral drugs that target stages of the hepatitis C virus reproductive cycle. They are more effective than older treatments such as ribavirin and interferon.
Which drugs are fusion inhibitors?
Examples include atazanavir (Reyataz), darunavir (Prezista), fosamprenavir (Lexiva), and ritonavir (Norvir). Entry or fusion inhibitors. Fusion inhibitors block the entry of HIV into CD4 cells. Examples include enfuvirtide (Fuzeon) and maraviroc (Selzentry).
Is NS5A a protease?
These include second-generation NS3/4 protease inhibitors, nucleoside and nonnucleoside NS5B polymerase inhibitors, and inhibitors of NS5A (a membrane-associated phosphoprotein that is part of the HCV RNA replication complex).