Proteases are one of the largest and best-characterized families of enzymes in the human proteome. Unfortunately, the understanding of protease function in the context of complex proteolytic cascades remains in its infancy. One major reason for this gap in understanding is the lack of technologies that allow direct assessment of protease activity. We report here an optimized solid-phase synthes...

Tumorigenesis is associated with several changes that alter the cellular susceptibility to programmed cell death. Here, we show that immortalization and transformation sensitize cells in particular to the cysteine cathepsin-mediated lysosomal death pathway. Spontaneous immortalization increased the susceptibility of wild-type murine embryonic fibroblasts (MEFs) to tumor necrosis factor (TNF)-me...

It has been proposed that the Plasmodium falciparum cysteine protease falcipain and aspartic proteases plasmepsin I and plasmepsin II act cooperatively to hydrolyze hemoglobin as a source of amino acids for erythrocytic parasites. Inhibitors of each of these proteases have potent antimalarial effects. We have now evaluated the antimalarial effects of combinations of cysteine and aspartic protea...

Breakdown of leaf proteins, particularly chloroplast proteins, is a massive process in senescing leaves. In spite of its importance in internal N recycling, the mechanism(s) and the enzymes involved are largely unknown. Senescence-associated vacuoles (SAVs) are small, acidic vacuoles with high cysteine peptidase activity. Chloroplast-targeted proteins re-localize to SAVs during senescence, sugg...

Calpastatin is an endogenous inhibitor of calpain (calcium-dependent cysteine protease). Calpastatin activityis highly related to the rate of protein turnover and rate of meat tenderization. In order to characterize thestructure of calpastatin in Iranian Afshari breed of sheep, intron 6 and partial exon 7 of the L domain wereamplified and sequenced. A fragment of approximately...

The Aspergillus nidulans pH-responsive transcription factor PacC is modulated by limited, two-step proteolysis. The first, pH-regulated cleavage occurs in the 24-residue highly conserved "signaling protease box" in response to the alkaline pH signal. This is transduced by the Pal signaling pathway, containing the predicted calpain-like cysteine protease and likely signaling protease, PalB. In t...

A cysteine protease was characterized from Symbiodinium sp. strain KB8 isolated from Cassiopea ornata. The protease was purified 36-fold with a yield of 1.8%, by four chromatographic steps using DE-52, DEAE-Toyopearl, MonoQ, and Superdex 200 HR. Among the six substrates tested, the enzyme showed highest activity toward t-butyloxycarbonyl-Val-Leu-Lys-4-methylcoumaryl-7-amide (Boc-VLK-MCA), and Z...

Extraction of protease from a local ginger rhizome (Zingiber officinale var. Bentong) was carried out. The effect of extraction pH (6.4, 6.8, 7.0, 7.2, 7.6, 8.0, 8.4, and 8.8) and stabilizers (0.2% ascorbic acid, 0.2% ascorbic acid and 5 mM EDTA, or 10 mM cysteine and 5 mM EDTA) on protease activity during extraction was examined. pH 7.0 potassium phosphate buffer and 10 mM cysteine in combinat...

Procerain B, a novel cysteine protease (endopeptidase) isolated from Calotropis procera belongs to Asclepiadaceae family. Purification of the enzyme, biochemical characterization and potential applications are already published by our group. Here, we report cDNA cloning, complete amino acid sequencing and molecular modeling of procerain B. The derived amino acid sequence showed high sequence ho...

Transgenic mice, homozygous for HIV-1 protease expression in the eye lens, display degradation of some lens crystallins and cytoskeletal proteins prior to cataract formation on postnatal days 23-25. Alterations to the internal lens hydration state also occur; therefore, the status of the aquaporin protein MIP26 was examined over postnatal days 16-25 to determine if it was altered during catarac...