scholarly journals Cystatin-like cysteine proteinase inhibitors from human liver

1984 ◽  
Vol 218 (3) ◽  
pp. 939-946 ◽  
Author(s):  
G D J Green ◽  
A A Kembhavi ◽  
M E Davies ◽  
A J Barrett

Cysteine proteinase inhibitor (CPI) forms from human liver were purified from the tissue homogenate by alkaline denaturation of cysteine proteinases with which they are complexed, acetone fractionation, affinity chromatography on S-carboxymethyl-papain-Sepharose and chromatofocusing. The multiple forms of CPI were shown immunologically to be forms of two proteins, referred to as CPI-A (comprising the forms of relatively acidic pI) and CPI-B (comprising the more basic forms). CPI-A and CPI-B are similar in their Mr of about 12400, considerable stability to pH2, pH11 and 80 degrees C, and tight-binding inhibition of papain, several related cysteine proteinases and dipeptidyl peptidase I. Ki values were determined for papain, human cathepsins B, H and L, and dipeptidyl peptidase I. The affinity of CPI-A for cathepsin B was about 10-fold greater than that of CPI-B, whereas CBI-B showed about 100-fold stronger inhibition of dipeptidyl peptidase I. For all the cysteine proteinases the liver inhibitors were somewhat less tight binding than cystatin. The resemblance of both CPI-A and CPI-B in several respects to egg-white cystatin is discussed. CPI-A seems to correspond to the epithelial inhibitor described previously, and CPI-B to the inhibitor from other cell types [Järvinen & Rinne (1982) Biochim. Biophys. Acta 708, 210-217].

2003 ◽  
Vol 77 (1) ◽  
pp. 21-26 ◽  
Author(s):  
T. Ikeda

AbstractThe involvement of intrinsic proteinases in the excystment of Paragonimus ohirai metacercariae was studied in in vitro excystment induced by sodium (Na) cholate, a bile salt and A23187, a Ca2+ ionophore. The effects of various proteinase inhibitors on the in vitro excystment were examined and similar inhibitory profiles were obtained. Benzyloxycarbonyl-L-leucyl-L-leucinal (Z-Leu-Leu-H), a cysteine proteinase inhibitor and 4-(2-aminoethyl)-benzenesulfonyl fluoride (Pefabloc SC), a serine proteinase inhibitor completely inhibited excystment, while L-3-carboxy-2,3-trans-epoxypropionyl-leucylamido (4-guanidino)-butane (E-64), a cysteine proteinase inhibitor and leupeptin, a cysteine/serine proteinase inhibitor permitted partial excystment at a lower rate, but inhibited it from proceeding from the partial excystment stage. In secretions released from metacercariae during excystment, proteinase activities detected towards various fluorogenic peptidyl substrates were almost completely inhibited by Z-Leu-Leu-H and E-64, but not by Pefabloc SC. Sodium cholate induced a higher secretion of cysteine proteinases and a higher rate of excystment than A23187. Profiles of cysteine proteinase activities towards five peptidyl substrates detected were markedly different among the two secretions and the lysate of newly excysted juveniles. Newly excysted juveniles released cysteine proteinases with similar activity profiles and levels to metacercariae induced by Na cholate-incubation, whereas the release of cysteine proteinases was reduced compared with metacercariae induced by A23187-incubation. These results provide valuable information about the involvement of intrinsic proteinases in metacercarial excystment.


1984 ◽  
Vol 220 (1) ◽  
pp. 147-155 ◽  
Author(s):  
M Pagano ◽  
F Esnard ◽  
R Engler ◽  
F Gauthier

The inhibition of human liver cathepsin L by two specific proteinase inhibitors present in human serum, namely alpha 2 cysteine-proteinase inhibitor and the low-Mr cysteine-proteinase inhibitor, was studied. Kinetic parameters, including inhibition constants (Ki) and rate constants for association and dissociation (k+1 and K-1), were determined. The values found are consistent with a possible physiological function of these inhibitors to control cathepsin L activity. Furthermore, a transfer of active proteinase from the complex with either cysteine-proteinase inhibitor species to alpha 2-macroglobulin was demonstrated in vitro. Given the rate of dissociation of both cathepsin-L-cysteine-proteinase inhibitor complexes, a function of transitory inhibitor can therefore be hypothesized for these proteins and might then provide an explanation of the clearance of lysosomal proteinases.


2002 ◽  
Vol 383 (5) ◽  
pp. 839-842 ◽  
Author(s):  
Natasa Sever ◽  
Metka Filipic ◽  
Joze Brzin ◽  
Tamara T. Lah

Abstract Various types of proteinases are implicated in the malignant progression of human and animal tumors. Proteinase inhibitors may therefore be useful as therapeutic agents in antiinvasive and antimetastatic treatment. The aims of this study were (1) to estimate the relative importance of proteinases in B16 cell invasion in vitro using synthetic, classspecific proteinase inhibitors and (2) to assess the inhibitory effect of some naturally occurring cysteine proteinase inhibitors. Serine proteinase inhibitor reduced invasiveness by up to 24%, whereas inhibition of aspartic proteinases reduced invasion by 11%. Synthetic inhibitors of cysteine proteinases markedly impaired invasion: cathepsin B inhibitors, particularly Ca 074Me, inhibited invasion from 20 40%, whereas cathepsin L inhibitor Clik 148 reduced invasion by 11%. The potato cysteine proteinase inhibitor PCPI 8.7 inhibited invasion by 21%, whereas another potato inhibitor, PCPI 6.6, and the mushroom cysteine proteinase inhibitor clitocypin had no effects. As the inhibitors that inhibited cathepsin B were in general more efficient at impairing the invasiveness, we conclude that of the two cysteine proteinases, cathepsin B plays a more important role than cathepsin L in murine melanoma cell invasion.


Parasitology ◽  
2017 ◽  
Vol 144 (13) ◽  
pp. 1695-1707 ◽  
Author(s):  
MARTÍN CANCELA ◽  
ILEANA CORVO ◽  
EDILEUZA DA SILVA ◽  
ALINE TEICHMANN ◽  
LEDA ROCHE ◽  
...  

SUMMARYCystatins are small, phylogenetically conserved proteins that are tight-binding inhibitors of cysteine proteinases. The liver flukeFasciola hepaticauses a diverse set of cysteine proteinases of the papain superfamily for host invasion, immune evasion and nutrition, but little is known about the regulation of these enzymes. The aim of this work is to characterize the cystatin repertoire ofF. hepatica. For this purpose, we first surveyed the available sequence databases, identifying three differentF. hepaticasingle-domain cystatins. In agreement with thein silicopredictions, at least three small proteins with cysteine proteinase binding activity were identified. Phylogenetic analyses showed that the three cystatins (named FhStf-1, -2 and -3) are members of the I25A subfamily (stefins). Whereas FhStf-1 grouped with classical stefins, FhStf-2 and 3 fell in a divergent stefin subgroup unusually featuring signal peptides. Recombinant rFhStf-1, -2 and -3 had potent inhibitory activity againstF. hepaticacathepsinLcysteine proteinases but differed in their capacity to inhibit mammalian cathepsinB,LandC. FhStf-1 was localized in theF. hepaticareproductive organs (testes and ovary), and at the surface lamella of the adult gut, where it may regulate cysteine proteinases related with reproduction and digestion, respectively. FhStf-1 was also detected amongF. hepaticaexcretion–secretion (E/S) products of adult flukes. This suggests that it is secreted by non-classical secretory pathway and that it may interact with host lysosomal cysteine proteinases.


1988 ◽  
Vol 107 (6) ◽  
pp. 2097-2107 ◽  
Author(s):  
J M Richardson ◽  
N A Woychik ◽  
D L Ebert ◽  
R L Dimond ◽  
J A Cardelli

Lysosomal enzymes are initially synthesized as precursor polypeptides which are proteolytically cleaved to generate mature forms of the enzymatically active protein. The identification of the proteinases involved in this process and their intracellular location will be important initial steps in determining the role of proteolysis in the function and targeting of lysosomal enzymes. Toward this end, axenically growing Dictyostelium discoideum cells were pulse radiolabeled with [35S]methionine and chased in fresh growth medium containing inhibitors of aspartic, metallo, serine, or cysteine proteinases. Cells exposed to the serine/cysteine proteinase inhibitors leupeptin and antipain and the cysteine proteinase inhibitor benzyloxycarbonyl-L-phenylalanyl-L-alanine-diazomethyl ketone (Z-Phe-AlaCHN2) were unable to complete proteolytic processing of the newly synthesized lysosomal enzymes, alpha-mannosidase and beta-glucosidase. Antipain and leupeptin treatment resulted in both a dramatic decrease in the efficiency of proteolytic processing, as well as a sevenfold increase in the secretion of alpha-mannosidase and beta-glucosidase precursors. However, leupeptin and antipain did not stimulate secretion of lysosomally localized mature forms of the enzymes suggesting that these inhibitors prevent the normal sorting of lysosomal enzyme precursors to lysosomes. In contrast to the results observed for cells treated with leupeptin or antipain, Z-Phe-AlaCHN2 did not prevent the cleavage of precursor polypeptides to intermediate forms of the enzymes, but greatly inhibited the production of the mature enzymes. The accumulated intermediate forms of the enzymes, however, were localized to lysosomes. Finally, fractionation of cell extracts on Percoll gradients indicated that the processing of radiolabeled precursor forms of alpha-mannosidase and beta-glucosidase to intermediate products began in cellular compartments intermediate in density between the Golgi complex and mature lysosomes. The generation of the mature forms, in contrast, was completed immediately upon or soon after arrival in lysosomes. Together these results suggest that different proteinases residing in separate intracellular compartments may be involved in generating intermediate and mature forms of lysosomal enzymes in Dictyostelium discoideum, and that the initial cleavage of the precursors may be critical for the proper localization of lysosomal enzymes.


1992 ◽  
Vol 3 (4) ◽  
pp. 307-332 ◽  
Author(s):  
Libuse A. Bobek ◽  
Michael J. Levine

The cystatin superfamily of proteins, derived from a common ancestor, is comprised of a diverse group of potent cysteine proteinase inhibitors and antibacterial/viral agents grouped into several families. This review concentrates on family 2 cystatins, namely, the human salivary cystatins and cystatin C. Emphasis is given to their physicochemical and functional properties at both the protein and the molecular level. The role of cystatins in disease processes, including those in the oral cavity, is also discussed. Finally, future directions for cystatin research in oral biology are presented.


2012 ◽  
Vol 24 (1) ◽  
pp. 211
Author(s):  
A. M. Lichtenauer ◽  
L. D. Spate ◽  
R. S. Prather ◽  
J. A. Green

Biochemical differences exist between oocytes that give rise to viable blastocysts and oocytes that give rise to embryos that are developmentally compromised. For example, specific proteolytic enzymes (e.g. cathepsin B) are transcriptionally abundant in in vitro-matured bovine oocytes from prepubertal heifers that have diminished developmental potential. The effects of the cysteine proteinase inhibitor, E-64, was recently investigated in bovine cumulus–oocyte complexes (COC) that represented both poor- and good-quality oocytes. Those reports revealed that the addition of E-64 promoted both oocyte maturation and subsequent embryo development. This project sought to determine if similar results would be obtained in a porcine oocyte/embryo culture system. Inclusion of 10 and 20 μM E-64 in maturation medium was performed. Maturation rates of porcine COC in 20 μM E-64 were elevated compared to those incubated in 10 μM E-64 (74% vs 53%; P < 0.05) or without E-64 (55%; P < 0.05: N = 1750 oocytes tested). Successful maturation to metaphase II was based on the presence of a polar body and a uniform cytoplasm 44 h after follicular aspiration. Based on these preliminary results and the earlier bovine work, it was hypothesized that the E-64 was having little influence on normal oocytes, but was promoting maturation of low-quality oocytes, possibly those that were beginning to degenerate. Consequently, 20 μM of E-64 was added to the maturation media of COC segregated based on morphological characteristics of the oocytes. Good COC had a homogeneous cytoplasm and greater than 3 layers of cumulus cells; the COC were considered poor if they displayed a nonhomogeneous cytoplasm and 1 layer or less of cumulus cells, yet were still considered fertilizable. Without E-64, an increase in maturation was measured when good oocytes were compared to poor oocytes (52% vs 29%; P < 0.05: N = 1600). No significant differences in maturation were observed between good oocytes incubated in the presence or absence of E-64. Likewise, no significant differences were observed between poor oocytes incubated in the presence or absence of E-64. The percentage of maturation of good oocytes cultured in E-64 was significantly higher than that of poor oocytes cultured with E-64 (67% vs 43%; P < 0.05). Maturation with the inhibitor did not significantly affect the subsequent cleavage or blastocyst rates of embryos that arose from these oocyte groups after fertilization. These experiments suggest that inhibition of cysteine proteinases significantly promotes oocyte maturation, as was seen in previous bovine work. Our data did not support the hypothesis that cysteine proteinase inhibition was selectively improving maturation of poor oocytes within the pool. It remains possible that increased maturation in good oocytes is a result of cysteine inhibition on juvenile oocytes that morphologically appeared good and the effect was less on already degenerated oocytes that appeared poor. Differences between treatments were determined by ANOVA with post-test by Tukey's multiple comparison test.


2001 ◽  
Vol 14 (4) ◽  
pp. 318-324 ◽  
Author(s):  
Torsten Hansen ◽  
Peter K Petrow ◽  
Andreas Gaumann ◽  
Gernot M Keyszer ◽  
Mike Otto ◽  
...  

2000 ◽  
Vol 35 (1) ◽  
pp. 70-76 ◽  
Author(s):  
T. C. Elden

The influence of leupeptin, a cysteine and serine proteinase inhibitor, on alfalfa weevil, Hypera postica (Gyllenhal), growth and development was investigated over nine successive generations. Concern that ingestion of proteinase inhibitors by phytophagous insects could induce production of inhibitor-insensitive proteinase activity initiated this investigation. The percent alfalfa weevil larval, pupal and adult survival, and defoliation was significantly lower on alfalfa foliage treated with leupeptin than on untreated foliage in all nine generations tested. Main effects for generations and treatment times generation were nonsignificant for all variables. This study demonstrates that after nine generations leupeptin, when compared to an untreated control, does not lose its ability to significantly inhibit alfalfa weevil growth and development. This suggests that the alfalfa weevil did not utilize or induce other proteinases (digestive enzymes) to compensate for inhibition of one of its major proteinases.


Parasitology ◽  
2004 ◽  
Vol 130 (2) ◽  
pp. 203-211 ◽  
Author(s):  
G. STEPEK ◽  
D. J. BUTTLE ◽  
I. R. DUCE ◽  
A. LOWE ◽  
J. M. BEHNKE

We examined the mechanism of action and compared the anthelmintic efficacy of cysteine proteinases from papaya, pineapple, fig, kiwi fruit and Egyptian milkweed in vitro using the rodent gastrointestinal nematode Heligmosomoides polygyrus. Within a 2 h incubation period, all the cysteine proteinases, with the exception of the kiwi fruit extract, caused marked damage to the cuticle of H. polygyrus adult male and female worms, reflected in the loss of surface cuticular layers. Efficacy was comparable for both sexes of worms, was dependent on the presence of cysteine and was completely inhibited by the cysteine proteinase inhibitor, E-64. LD50 values indicated that the purified proteinases were more efficacious than the proteinases in the crude latex, with purified ficin, papain, chymopapain, Egyptian milkweed latex extract and pineapple fruit extract, containing fruit bromelain, having the most potent effect. The mechanism of action of these plant enzymes (i.e. an attack on the protective cuticle of the worm) suggests that resistance would be slow to develop in the field. The efficacy and mode of action make plant cysteine proteinases potential candidates for a novel class of anthelmintics urgently required for the treatment of humans and domestic livestock.


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