Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nine virus-specified proteins were identified by SDS-polyacrylamide gel electrophoresis in [35S]methionine-labelled chick embryo cells infected with tick-borne encephalitis (TBE) virus by comparison with mock-infected cells. These proteins were designated P91, p74, p72, P67, GP53(E), P47, p25, P15(C) and P14.5 according to their molecular weights. Peptide mapping of P91, P67, GP53(E) and P47 from TBE virus-infected cells, as well as those of the corresponding proteins from West Nile virus (WNV)-infected cells (previously termed NV5, NV4, V3 and NV3), demonstrated the uniqueness of these proteins. Almost no subtype variability, with respect to the pattern of intracellular proteins, was found when isolates of TBE virus from Austria, Switzerland, Germany, Finland and Czechoslovakia were compared. Peptide mapping of NV5 (P91) and NV4 (P67) from all these isolates using limited proteolysis with alpha-chymotrypsin and V8 protease revealed completely identical patterns, thus extending our observations that TBE virus seems to represent a very stable member of the flavivirus genus, which was based on the lack of variation found with the structural glycoprotein. On the other hand, the Far Eastern subtype of TBE virus and the closely related louping-ill virus could not only be differentiated from the Western subtype by differences in the peptide maps of their structural glycoprotein but also in those of the non-structural protein NV5, i.e. subtype or subgroup variations are not confined to the virion surface glycoprotein. WNV and Murray Valley encephalitis virus (MVEV) revealed the expected heterogeneity of virus-specified proteins found in cells infected with different flaviviruses. It is especially interesting that also the largest non-structural protein, NV5, is subject to this heterogeneity, ranging in mol. wt. from 91 000 for TBE virus to 98 000 for MVEV and that also the peptide maps of NV5, as well as those of NV4, were unrelated. These proteins, therefore, revealed a variability between serologically distinct flaviviruses similar to that observed with the structural glycoprotein.
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PMID:Molecular epidemiology of tick-borne encephalitis virus: peptide mapping of large non-structural proteins of European isolates and comparison with other flaviviruses. 629 51

Arthropod cuticles play an important role as the first barrier against invading pathogens. We extensively determined the sequences of horseshoe crab cuticular proteins. Proteins extracted from a part of the ventral side of the cuticle were purified by chitin-affinity chromatography, and separated by two-dimensional SDS/PAGE. Proteins appearing on the gel were designated high molecular mass chitin-binding proteins, and these proteins were then grouped into classes based on their approximate isoelectric points and predominant amino acid compositions. Members of groups designated basic G, basic Y, and acidic S groups contained a so-called Rebers and Riddiford consensus found in arthropod cuticular proteins. Proteins designated acidic DE25 and DE29 each contained a Cys-rich domain with sequences similar to those of insect peritrophic matrix proteins and chitinases. In contrast, basic QH4 and QH10 contained no consensus sequences found in known chitin-binding proteins. Alternatively, a low molecular mass chitin-binding fraction was prepared by size exclusion chromatography, and 15 low molecular mass chitin-binding proteins, named P1 through P15, were isolated. With the exception of P9 and P15, all were found to be identical to known antimicrobial peptides. P9 consisted of a Kunitz-type chymotrypsin inhibitor sequence, and P15 contained a Cys-rich motif found in insulin-like growth factor-binding proteins. Interestingly, we observed transglutaminase-dependent polymerization of nearly all high molecular mass chitin-binding proteins, a finding suggests that transglutaminase-dependent cross-linking plays an important role in host defense in the arthropod cuticle, analogous to that observed in the epidermal cornified cell envelope in mammals.
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PMID:Comprehensive sequence analysis of horseshoe crab cuticular proteins and their involvement in transglutaminase-dependent cross-linking. 1615 96