Investigations have been carried out on proteolytic activities of four laticiferous plants, viz. Calotropis procera (Ait.) R. Br. (Ruie), Carica papaya Linn. (Papaya), Euphorbia nivulia Buch.-Ham. (Sabar) and Ficus carica Linn. (Anjir) using Hammerstein grade casein and skimmed milk powder. Ratio of milk clotting to proteolytic activity was highest in the latex sample of C. papaya followed by F...

We have examined by gelatin-SDS-PAGE the protease activity in cell lysates of Giardia duodenalis trophozoites of two axenic strains isolated in Brazil from a symptomatic patient (BTU-11) and an asymptomatic carrier (BTU-10), and the reference strain Portland 1 (P1). The proteolysis band patterns showed differences among strains isolated from asymptomatic and symptomatic individuals. The lysate ...

The present study aimed to investigate, as a follow-up of microarray profiling, the expression of the lysosomal cysteine protease cathepsin S and that of its endogenous inhibitor cystatin C in the most common primary intraocular tumor in adults, uveal melanoma. The expression pattern unveiled was characterized by a relative increase in the active form of the elastolytic and collagenolytic cathe...

Newly replicated Plasmodium falciparum parasites escape from host erythrocytes through a tightly regulated process that is mediated by multiple classes of proteolytic enzymes. However, the identification of specific proteases has been challenging. We describe here a forward chemical genetic screen using a highly focused library of more than 1,200 covalent serine and cysteine protease inhibitors...

The cysteine protease cruzipain is considered to be a validated target for therapeutic intervention in the treatment of Chagas disease. Anti-trypanosomal activity against the CL Brener strain of T. cruzi was observed in the 0.1 μM to 1 μM range for three nitrile-based cysteine protease inhibitors based on two scaffolds known to be associated with cathepsin K inhibition. The two compounds showin...

Mutation of the tobacco etch virus (TEV) protease nucleophile from cysteine to serine causes an approximately ∼104 -fold loss in activity. Ten rounds of directed evolution of the mutant, TEVSer , overcame the detrimental effects of nucleophile exchange to recover near-wild-type activity in the mutant TEVSer X. Rather than respecialising TEV to the new nucleophile, all the enzymes along the evol...

Bacteroides amylophilus strain H I 8 produced protease(s), active at pH 7.0, when grown anaerobically in a simple maltose, ammonium sulphate, cysteine, sodium bicarbonate and salts medium. Protease production was neither induced nor repressed by a wide range of nutrients. Protease was synthesized by exponentially growing organisms and 20% of it was liberated into the growth medium. The cell-bou...

Calpains and caspases are two cysteine protease families that play important roles in regulating pathological cell death. Here, we report that m-calpain may be responsible for cleaving procaspase-12, a caspase localized in the ER, to generate active caspase-12. In addition, calpain may be responsible for cleaving the loop region in Bcl-xL and, therefore, turning an antiapoptotic molecule into a...

Atherosclerotic cardiovascular disease (ASCVD) is an inflammatory disease characterized by extensive arterial wall matrix protein degradation. Cysteine protease cathepsins play a pivotal role in extracellular matrix (ECM) remodeling and have been implicated in the development and progression of atherosclerosis-based cardiovascular diseases. An imbalance in expression between cathepsins (such as...

Cystatins are cysteine protease inhibitors that are at the front-line of defense against pathogens that secrete proteases as virulence factors. In this issue, Vincents et al. (2008) reveal how the bacterial protease IdeS from Streptococcus pyogenes hijacks normal cystatin C function to convert it into a cofactor that enhances proteolytic destruction of host-defense antibodies.