Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Antibody against purified bovine cathepsin D was raised in rabbits, and the polyclonal antiserum was tested to determine its ability to inhibit the hemoglobinolytic activity of the crude enzyme preparation (CEP) from adult Schistosoma japonicum and its effect upon in vitro cultured Schistosoma mansoni schistosomules. The 100,000 g supernatant fraction (CEP) from lyophilized adult worms was preincubated with antiserum and subsequently incubated with hemoglobin. Hemoglobinolytic activity was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoretic procedures. Five hours of incubation failed to diminish hemoglobin concentration in experimentals, whereas controls treated with preimmune serum displayed hemoglobin degradation. Pepstatin inhibited hemoglobin degradation. Western blot analysis of the CEP revealed a broad band of activity at approximately 45 kDa. Schistosomules incubated in vitro either in the antiserum or pepstatin and subsequently exposed to host erythrocytes showed a marked inhibition of digestive activities. Although structural changes were not evident in the gastrodermis, some perturbation of the tegument was observed. Schistosomules fed host erythrocytes and postincubated in the antiserum displayed increased tegumental perturbation and extensive alteration of the gastrodermis, including dilation of cisternae and membrane disruption. Schistosomules exposed to preimmune serum were normal in all respects.
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PMID:Schistosoma japonicum: immunoinhibitory studies on hemoglobin digestion using heterologous antiserum to bovine cathepsin D. 159 88

Results from previous biochemical and cytochemical studies show that a pepstatin-sensitive hemoglobinase is present in the gastrodermis of adult Schistosoma japonicum. To determine whether there is structural similarity to mammalian cathepsin D in addition to inhibition similarity, an immunocytochemical study was initiated using heterologous antiserum to bovine cathepsin D. With light microscopy, immunostaining was observed in the cecal lumen, the gastrodermis, and on the dorsal tegument and tubercles of male worms. With transmission electron microscopy, immunostaining was observed in gastrodermal autophagosomes and tegumental invaginations of the dorsal tegument of males. Immunostaining was also observed within the tubercles, but the reaction product did not appear to be associated with any definite structure or organelle. Heavy endogenous peroxidase activity in the cecal lumen due to ingested hemoglobin obscured with immunostaining. Assuming that all immunostaining is due to molecules that function in a manner similar to that of cathepsin D, it is suggested that such molecules may regulate some aspect of the host-parasite relationship and/or the parasite's metabolism. Alternatively, the immunostained molecules may be structural proteins with epitopes similar to those of mammalian cathepsin D. Reactions associated with the cecum, however, on the basis of previous studies, are believed to derive from molecules that are proteolytic enzymes.
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PMID:Schistosoma japonicum: immunocytochemistry of adults using heterologous antiserum to bovine cathepsin D. 311 14

An acid proteinase of Dirofilaria immitis worms was purified 437-fold by gel filtration on Sephadex G-75 followed by pepstatin-Agarose gel affinity chromatography. The enzyme with a molecular weight of 42 kDa was homogeneous as judged by both affinity chromatography and SDS-polyacrylamide gel electrophoresis. Polyacrylamide disc electrophoresis at pH 8.9, however, revealed that the enzyme was composed of five multi-forms, all carrying proteinase activity. Optimum pH of the enzyme was in the range of pH 2.8 to 3.4, and its isoelectric point ranged between 5.8 and 6.4. The purified proteinase showed a potent activity against hemoglobin and myoglobin releasing acid soluble peptides, but not free amino acids. When enzymatic properties of the proteinase was compared with mammalian cathepsin D and pepsin, D. immitis proteinase activity was reduced to about 80% of the initial activity by incubating at neutral pH and 50 degrees C for 5 min, just like cathepsin D, which remained intact. Pepsin activity was completely destroyed under the same condition. An aspartic proteinase inhibitor, 1,2-epoxy-3-(p-nitrophenoxy)propane, which inhibited pepsin by 30% at 37 degrees C for 10 min, did show little effects on D. immitis proteinase and cathepsin D. Inhibitory effect of diazoacetyl-DL-norleucine methyl ester (DAN) on D. immitis proteinase was intermediate (50% after 60 min). Immunolocalization of the proteinase in the worm tissue using its monoclonal antibodies revealed that the enzyme was localized in the intestine as well as uterine wall and some small granules of microfilariae in the uterus.
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PMID:Purification and characterization of an acid proteinase from Dirofilaria immitis worms. 854 Mar 32

Many parasites have deployed proteinases to accomplish some of the tasks imposed by a parasitic life style, including tissue penetration, digestion of host tissue for nutrition and evasion of host immune responses. Information on proteinases from trematodes, cestodes and nematode parasites is reviewed, concentrating on those worms of major medical and economical importance. Their biochemical characterization is discussed, along with their putative biological roles and, where available, their associated genes. For example, proteinases expressed by the various stages of the schistosome life-cycle, in particular the well-characterized cercarial elastase which is involved in the penetration of the host skin and the variety of proteinases, such as cathepsin B (Sm31), cathepsin L1, cathepsin L2, cathepsin D, cathepsin C and legumain (Sm32), which are believed to be involved in the catabolism of host haemoglobin. The various endo- and exoproteinases of Fasciola hepatica, the causative agent of liver fluke disease, are reviewed, and recent reports of how these enzymes have been successfully employed in cocktail vaccines are discussed. The various proteinases of cestodes and of the diverse superfamilies of parasitic nematodes are detailed, with special attention being given to those parasites for which most is known, including species of Taenia, Echinococcus, Spirometra, Necator, Acylostoma and Haemonchus. By far the largest number of papers in the literature and entries to the sequence data bases dealing with proteinases of parasitic helminths report on enzymes belonging to the papain superfamily of cysteine proteinases. Accordingly, the final section of the review is devoted to a phylogenetic analysis of this superfamily using over 150 published sequences. This analysis shows that the papain superfamily can be divided into two major branches. Branch A contains the cathepin Bs, the cathepsin Cs and a novel family termed cathepsin Xs, while Branch B contains the cruzipains, cathepsin Ls, papain-like and aleurain/cathepsin H-like proteinases. The relationships of the helminth proteinases, and similar proteinases from protozoan parasites and other organisms, within these groups are discussed.
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PMID:Proteinases and associated genes of parasitic helminths. 1021 92

DNA-based vaccine technology was used to immunize against the schistosome digestive enzyme, cathepsin D aspartic proteinase. The cDNA coding for Schistosomajaponicum aspartic proteinase was cloned in a mammalian expression vector under control of the CMV promoter/enhancer and expressed for the first time in transfected mammalian cells as well as in mice immunized--by means of intra-ear pinna injection--with the aspartic proteinase-encoding DNA construct. Mice developed antibodies which recognized the native protein in homogenates of S. japonicum worms and reacted with the gut and, to a much lesser degree, with the parenchyma of the parasites in cryostat sections. It was noteworthy that the vaccinated mouse sera did not detectably cross-react with S. mansoni antigens either in homogenates or on cryostat sections. By contrast, infection sera of mice or humans strongly cross-reacted with both schistosome species. We conclude that DNA vaccination can induce species-restricted antibody responses against schistosome proteins. The implications of this previously unrecognized specificity are discussed.
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PMID:Species-restricted antibody response against a DNA-construct coding for aspartic proteinase from Schistosoma japonicum. 1199 27

A proteolytic activity was identified in Dugesia tigrina planaria using the chromogenic substrate Phe-Ala-Ala-Phe (4-NO2)-Phe-Val-Leu-O4MP. The activity of the enzyme increased four times during the regeneration and presented a maximum at 120 hr being higher in tail than head regenerating segments. The protease that displays this activity was purified from worms by a single step on pepstatin-agarose followed by gel-filtration high performance liquid chromatography. The purification resulted in a 34-fold increase in specific activity and the final yield was 10%. The active D. tigrina hydrolase appears to be a dimeric protein composed of identical subunits with 34 kDa associated by disulphide bridges similar to vertebrate cathepsin D. By SDS-PAGE several bands were detected but upon gel filtration HPLC one proteolytically active component, termed Asp-68, was detected and isolated. The maximal activity was observed in a range between pH 3.5-5.0 and the enzyme became inactivated at a pH value above 7.2. The purified enzyme was not inhibited by inhibitors from serine (aprotinin, TPCK, PMSF and TLCK), metallo (EDTA) and cysteine proteinase (E-64) classes. In contrast, inhibitors such as pepstatin, EPNP, and 4-beta-PMA efficiently inhibited the activity of the 68-kDa protease.
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PMID:Aspartic proteinase in Dugesia tigrina (Girard) planaria. 1213 99

Hookworms routinely reach the gut of nonpermissive hosts but fail to successfully feed, develop, and reproduce. To investigate the effects of host-parasite coevolution on the ability of hookworms to feed in nonpermissive hosts, we cloned and expressed aspartic proteases from canine and human hookworms. We show here that a cathepsin D-like protease from the canine hookworm Ancylosotoma caninum (Ac-APR-1) and the orthologous protease from the human hookworm Necator americanus (Na-APR-1) are expressed in the gut and probably exert their proteolytic activity extracellularly. Both proteases were detected immunologically and enzymatically in somatic extracts of adult worms. The two proteases were expressed in baculovirus, and both cleaved human and dog hemoglobin (Hb) in vitro. Each protease digested Hb from its permissive host between twofold (whole molecule) and sixfold (synthetic peptides) more efficiently than Hb from the nonpermissive host, despite the two proteases' having identical residues lining their active site clefts. Furthermore, both proteases cleaved Hb at numerous distinct sites and showed different substrate preferences. The findings suggest that the paradigm of matching the molecular structure of the food source within a host to the molecular structure of the catabolic proteases of the parasite is an important contributing factor for host-parasite compatibility and host species range.
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PMID:Cleavage of hemoglobin by hookworm cathepsin D aspartic proteases and its potential contribution to host specificity. 1220 47

An immunohistochemical method using antibodies against polycyclic aromatic hydrocarbons (PAHs) and dioxins was developed on frozen tissue sections of the earthworm Eisenia andrei exposed to environmentally relevant concentrations of benzo[a]pyrene (B[a]P) (0.1, 10, 50 ppm) and 2,3,7,8-tetrachloro-dibenzo-para-dioxin (TCDD) (0.01, 0.1, 2 ppb) in spiked standard soils. The concentrations of B[a]P and TCDD in E. andrei exposed to the same conditions were also measured using analytical chemical procedures. The results demonstrated that tissues of worms exposed to even minimal amount of B[a]P and TCDD reacted positively and specifically to anti-PAHs and -dioxins antibody. Immunofluorescence revealed a much more intense staining for the gut compared to the body wall; moreover, positively immunoreactive amoeboid coelomocytes were also observed, i.e. cells in which we have previously demonstrated the occurrence of genotoxic damage. The double immunolabelling with antibodies against B[a]P/TCDD and the lysosomal enzyme cathepsin D demonstrated the lysosomal accumulation of the organic xenobiotic compounds, in particular in the cells of the chloragogenous tissue as well as in coelomocytes, involved into detoxification and protection of animals against toxic chemicals. The method described is timesaving, not expensive and easily applicable.
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PMID:Immunofluorescence detection and localization of B[a]P and TCDD in earthworm tissues. 2441 5