Papain

Papain, a cysteine protease of the peptidase C1 family, is utilized in the food, pharmaceutical, textile, and cosmetic industries.

L-Cystine (Cystine Acid) is not considered one of the 20 amino acids, L-Cystine (Cystine Acid) is a sulfur-containing derivative obtained from oxidation of cysteine amino acid thiol side chains. It functions as an antioxidant and protects tissues against radiation and pollution, slowing the aging process. It also aids protein synthesis. L-Cystine (Cystine Acid) is abundant in many proteins of skeletal tissues and skin, and found in insulin and digestive enzymes chromotrypsinogen A, papain, and trypsinogen.

4'-O-Methylbavachalcone (O-Methylbroussochalcone B) is isolated from Psoralea corylifolia, inhibits severe acute respiratory syndrome coronavirus (SARS-CoV) papain-like protease (PLpro) activity (IC50: 10.1 μM).

Chymostatin B is a subtype of Chymostatin distinguished by the presence of a valine residue. Chymostatin inhibits chymotrypsin, papain, as well as other serine/cysteine endopeptidases.

Bacithrocin D (Thiolstatin D) inhibits various proteases and has the capability to prolong clotting time. It exhibits IC50 values of 124, 9, 0.85, and 0.01 μM against thrombin, factor Xa, trypsin, and papain, respectively.

Laccaridione B inhibits the activity of serine proteases. It exhibits inhibitory effects on trypsin, papain, thermolysin, collagenase, and zinc metalloprotease with IC50 values of 10.9 μg/mL, 5.1 μg/mL, 8.4 μg/mL, 5.7 μg/mL, and 3.0 μg/mL, respectively. Additionally, Laccaridione B shows significant antiproliferative activity against L-929, K-562, and HeLa cells, with IC50 values of 2.4 μg/mL, 1.8 μg/mL, and 13.9 μg/mL, respectively.

Bacithrocin C is a thrombin inhibitor that suppresses the activity of thrombin, factor Xa, trypsin, and papain, with IC50 values of 80 μM, 15 μM, 1.3 μM, and 0.02 μM, respectively.

Bacithrocin B is a thrombin inhibitor that suppresses the activity of thrombin, Factor Xa, trypsin, and papain, with IC50 values of 84 μM, 17 μM, 1.7 μM, and 0.02 μM, respectively.

Bacithrocin C is a thrombin inhibitor that also suppresses factor Xa, trypsin, and papain, with IC50 values of 48 μM, 13 μM, 0.65 μM, and 0.02 μM, respectively.

Aureoquinone is a broad-spectrum proteinase (protease) inhibitor. It inhibits trypsin, papain, thermolysin, collagenase, and pronase, with IC50 values of 11.4 μg mL, 14.5 μg mL, 17.8 μg mL, 7.1 μg mL, and 8.7 μg mL, respectively.

Estatin B is a thiol protease inhibitor that can be found in the thermophilic bacterium M4323, and it exhibits specificity towards thiol proteases such as papain, fig protease, and bromelain. In mice, Estatin B suppresses the production of IgE antibodies without affecting the production of IgG.

Chymostatin C is a variant of Chymostatin, distinguished by the presence of an isoleucine residue. Chymostatin inhibits chymotrypsin, papain, and other serine/cysteine endopeptidases.

Laccaridione A can inhibit the activity of anti-serine proteases. The IC50 values of Laccaridione A for inhibiting trypsin, papain, thermolysin, collagenase, and zinc proteases are 14.7 μg/mL, 2.5 μg/mL, 18.8 μg/mL, 7.2 μg/mL, and 18.2 μg/mL, respectively.