Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.64 (proteinase K)
 4,071 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interaction of Anaplasma marginale initial bodies with the bovine erythrocyte surface was examined by a direct hemagglutination assay. Purified initial bodies were shown to specifically hemagglutinate bovine erythrocytes but not erythrocytes from nonhost animal species. Hemagglutination was inhibited by treatment of purified initial bodies with trypsin, alpha-chymotrypsin, or proteinase K but not by treatment with neuraminidase or sodium periodate. Treatment of bovine erythrocytes with alpha-chymotrypsin or neuraminidase partially inhibited hemagglutination of the treated cells by initial bodies. In contrast, no inhibition occurred after treatment of erythrocytes with trypsin, phospholipases, or sodium periodate or when monosaccharides and disaccharides were used as potential competitive inhibitors. Thus, the initial body receptor is probably a surface protein, whereas the bovine receptor may comprise both protein and carbohydrate. Hemagglutination was unaffected by treatment of initial bodies with monoclonal or polyclonal antibodies raised against the A. marginale 31-kDa (MSP4) major surface polypeptide or non-A. marginale proteins or by treatment with a monoclonal antibody to the A. marginale MSP1a neutralization-sensitive epitope. In contrast, antiserum raised against whole A. marginale initial bodies or monospecific antibodies raised against purified A. marginale major surface polypeptides with molecular sizes of 105 (MSP1a), 100 (MSP1b), 61, and 36 (MSP2) kDa completely or partially inhibited hemagglutination. These data confirm the proposed surface location of the proteins susceptible to inhibition and suggest that they mediate hemagglutination of bovine erythrocytes. We propose that these surface proteins are possible adhesins.
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PMID:Characterization of hemagglutinating components on the Anaplasma marginale initial body surface and identification of possible adhesins. 792 25

We incubated yeast cells (Saccharomyces cerevisiae) with the methyl donor S-adenosyl-L-[methyl-3H]methionine and then fractionated their cellular components by gel electrophoresis in sodium dodecyl sulfate. By analyzing gel slices for [3H]methyl esters by a vapor-phase diffusion assay, we detect major methyl-esterified species that migrate at apparent polypeptide sizes of 24 and 22 kDa and minor species of 49, 38, 35, 33, 31, and 26 kDa. Incubation of extracts from labeled cells with ribonuclease A or proteinase K revealed that the 24- and 22-kDa species represent methyl-esterified RNAs, whereas the other species are methyl-esterified polypeptides. The 38-, 33-, 31-, and 26-kDa polypeptides were not methyl-esterified in an isogenic yeast strain lacking the STE14 gene encoding a C-terminal isoprenylcysteine methyltransferase, suggesting that they are substrates for the STE14 methyltransferase. On the other hand, the amount of the methylated 49-kDa polypeptide is reduced in the ste14 mutant, indicating that at least two methylated polypeptides are present--one a substrate of the STE14 methyltransferase and one a substrate of a STE14-independent methyltransferase. The 35-kDa polypeptide also appears to be methylated by a STE14-independent methyltransferase. When cells were incubated in the presence of the protein synthesis inhibitor cycloheximide, little or no methylation of the STE14-dependent species was detected while the methylation of the STE14-independent substrates was unaffected. Pulse-chase studies revealed significant turnover of all of the methylated species in a 4-h period, with the exception of the 38-kDa polypeptide.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Protein carboxyl methylation in Saccharomyces cerevisiae: evidence for STE14-dependent and STE14-independent pathways. 806 61

Proteinase K from the fungus Tritirachium album Limber binds two Ca2+ ions, one strongly (Ca 1) and the other weakly (Ca 2). Removal of these cations reduces the stability of proteinase K as shown by thermal denaturation, but the proteolytic activity is unchanged. The x-ray structures of native and Ca(2+)-free proteinase K at 1.5-A resolution show that there are no cuts in the polypeptide backbone (i.e. no autolysis), Ca 1 has been replaced by Na+, while Ca 2 has been substituted by a water associated with a larger but locally confined structural change at that site. A small but concerted geometrical shift is transmitted from the Ca 1 site via eight secondary structure elements to the substrate recognition site (Gly100-Tyr104, and Ser132-Gly136) but not to the catalytic triad (Asp39,His69,Ser224). This is accompanied by positional changes of localized waters.
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PMID:Crystal structure of calcium-free proteinase K at 1.5-A resolution. 808 13

A 45 kDa polypeptide capable of erythrocyte (RBC) lysis and hemoglobin oxidation was isolated from Treponema denticola, ATCC 35404 (TD-4) after sequential ammonium sulfate (2.8-3.6 M) precipitation and preparative electrophoresis. The purified polypeptide produced a single protein band on PAGE at a relative molecular weight of 45 kDa in the presence and absence of SDS. The polypeptide was sensitive to proteinase K and pronase, and heating at 80 degrees C. The protease inhibitors, PMSF, TLCK and benzamidine had no inhibitory affect on activity. It was non heat-modifiable, and lost all hemolytic and hemoxidative function in SDS. Cysteine and other sulfhydryl-containing compounds were required for hemolytic and hemoxidative activities. The isoelectric point of the polypeptide was 5.3 and N'-terminal sequence analysis indicated it to belong to a new, so far undescribed group of peptides possessing hemoxidation and hemolytic activities. Functionally, it was capable of rapid hemoxidation of sheep and human erythrocytes (hemoglobin to methemoglobin) coupled to erythrocyte lysis, or hemolysis.
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PMID:Purification and characterization of a 45 kDa hemolysin from Treponema denticola ATCC 35404. 809 78

The Neurospora plasma membrane H(+)-ATPase is a polytopic integral membrane protein. To localize transmembrane segments, mutants were constructed that contained the amino and carboxyl termini of the H(+)-ATPase with putative transmembrane segment. A stretch of amino acid residues from yeast invertase that has three consensus N-linked glycosylation sites was placed carboxyl terminal of the putative transmembrane segment. RNA transcripts of these mutants were translated in a Neurospora in vitro system that was supplemented with microsomes from Neurospora. By the criteria of glycosylation of the polypeptide chain, resistance to extraction at pH 11.5, and protection from proteinase K digestion, only one transmembrane segment could be identified within the amino acid residues 272-314 of the primary sequence of the H(+)-ATPase.
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PMID:Topology of the Neurospora plasma membrane H(+)-ATPase. Localization of a transmembrane segment. 810 34

For the first time reactivation of cell extract of three strains of Propionibacterium shermanii in UV inactivated not filament-forming strain Escherichia colli AB 1157 is shown. Reactivation was demonstrated in preincubated and postincubated test-culture and increased as survival of E. coli decreased in a range 1.8-0.006%. The factor (factors) of defense is dialysable, thermolabile and is present as in a fraction of nucleoproteins and nucleic acids so in a fraction of soluble proteins. The extracts were inactivated by incubation with proteinase K and trypsin, partly decreased activity by incubation with alpha-amylase and selected nuclease but not with lipase. Polypeptide nature of reactivating factor is supposed.
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PMID:[Reactivation of Escherichia coli inactivated by ultraviolet light by cell extracts of propionic acid bacteria]. 811 46

Sm23, a surface protein of the human parasite Schistosoma mansoni, belongs to the family of "cysteine-rich, hydrophobic proteins," which are expressed on mammalian hematopoietic cells or tumor cells. Sm23 shares the highly conserved hydrophobicity profile of these proteins, which predicts four transmembrane segments, but is in addition linked to the membrane by a glycosylphosphatidylinositol (GPI) anchor. Our results suggest that Sm23 uses both the potential transmembrane domains and the GPI anchor for membrane insertion: (a) Sm23 was not released from the surface after cleavage with phosphatidylinositol-specific phospholipase C (PIPLC). (b) In a Triton X-114 phase-separation system, native [3H]ethanolamine- or [35S]methionine-labeled Sm23 partitioned into the detergent phase. Upon removal of the GPI anchor by PIPLC, the majority of the molecules stayed in the detergent-phase as expected of a transmembrane protein. (c) When full-length recombinant Sm23 was transcribed and translated in vitro, the polypeptide chain was inserted into microsomal membranes: Sm23 stayed associated with the membranes when they were incubated with carbonate buffer at pH 11.5, and membrane bound Sm23 was protected from digestion with proteinase K. (d) Recombinant Sm23, when expressed in the baculovirus expression system, was transported to the surface of infected insect cells, and similarly to the native protein it was not released from these cells after cleavage with PIPLC.
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PMID:Schistosoma mansoni: Sm23 is a transmembrane protein that also contains a glycosylphosphatidylinositol anchor. 816 Nov 93

The Vibrio fischeri luminescence (lux) genes are activated at sufficiently high culture densities by the transcriptional activator LuxR in combination with a diffusible signal compound termed autoinducer. We have used antibodies directed against LuxR in immunoprecipitation experiments to study the subcellular location of this transcription factor. The LuxR polypeptide was detected in membranes and not in the soluble pool of cytoplasmic proteins from V. fischeri. LuxR was not released from the membranes by 0.6 M KCl or by the nonionic detergents Nonidet P-40, N-octyl-beta-D-glucopyranoside, and Triton X-100. LuxR and a number of other V. fischeri proteins were released from the membranes by EDTA. The autoinducer had no detectable influence on the subcellular location of LuxR. In spheroplasts, neither the abundance nor the molecular mass of the LuxR antigen was influenced by treatment with proteinase K. Together with other information, these results indicate that LuxR is an amphipathic protein that is associated with the cytoplasmic membrane of V. fischeri.
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PMID:The Vibrio fischeri luminescence gene activator LuxR is a membrane-associated protein. 822 77

The protein crystals found in potato (Solanum tuberosum L.) tuber cells consist of a single 85-kD polypeptide. This polypeptide is an inhibitor of papain and other cysteine proteinases and is capable of binding several proteinase molecules simultaneously (P. Rodis, J.E. Hoff [1984] Plant Physiol 74: 907-911). We have characterized this unusual inhibitor in more detail. Titrations of papain activity with the potato papain inhibitor showed that there are eight papain binding sites per inhibitor molecule. The inhibition constant (Ki) value for papain inhibition was 0.1 nM. Treatment of the inhibitor with trypsin resulted in fragmentation of the 85-kD polypeptide into a 32-kD polypeptide and five 10-kD polypeptides. The 32-kD and 10-kD fragments all retained the ability to potently inhibit papain (Ki values against papain were 0.5 and 0.7 nM, respectively) and the molar stoichiometries of papain binding were 2 to 3:1 and 1:1, respectively. Other nonspecific proteinases such as chymotrypsin, subtilisin Carlsberg, thermolysin, and proteinase K also cleaved the 85-kD inhibitor polypeptide into functional 22-kD and several 10-kD fragments. The fragments obtained by digestion of the potato papain inhibitor with trypsin were purified by reverse-phase high-performance liquid chromatography, and the N-terminal amino acid sequence was obtained for each fragment. Comparison of these sequences showed that the fragments shared a high degree of homology but were not identical. The sequences were homologous to the N termini of members of the cystatin superfamily of cysteine proteinase inhibitors. Therefore, the inhibitor appears to comprise eight tandem cystatin domains linked by preteolytically sensitive junctions. We have called the inhibitor potato multicystatin (PMC). By immunoblot analysis and measurement of papain inhibitory activity, PMC was found at high levels in potato leaves (up to 0.6 microgram/g fresh weight tissue), where it accumulated under conditions that induce the accumulation of other proteinase inhibitors linked to plant defense. PMC may have a similar defensive role, for example in protecting the plant from phytophagous insects that utilize cysteine proteinases for dietary protein digestion.
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PMID:Proteolysis of the 85-kilodalton crystalline cysteine proteinase inhibitor from potato releases functional cystatin domains. 829 Jun 29

Dengue type 2 virus (DV)-induced suppressor cytokine (SF) binds to macrophages to transmit the suppressor signal to recruit the second subpopulation of suppressor T cells. The present study was undertaken to identify and purify the receptor for SF (SF-R) on macrophages. The binding of 125I-SF to macrophages was saturable and reversible. Scatchard analysis showed the presence of both high (54,000/cell) and low (1.78 x 10(6)/cell) affinity receptor sites. The binding of 125I-SF to macrophages was inhibited by pretreatment of macrophages with anti-SF antiserum but not by a heterologous antiserum. Normal mouse peritoneal macrophage membrane was solubilized with Triton-X-100 and the components separated by low pressure liquid chromatography (LPLC) to purify SF-R. The presence of SF binding moiety (SF-R) was screened at each step of purification. The purified SF-R resolved into two bands of 45-50 kD mol. wt on SDS-PAGE. 125I-SF+SF-R complex run on SDS-PAGE showed a single band at about 55-60 kD mol. wt by autoradiography. Anti-SF-R antiserum reacted with SF-R in a Western blot test; the reaction was abolished by pretreatment of the blots with proteinase K, but not by pretreatment with periodic acid. SF-R was composed of two polypeptide chains (alpha and beta) which were obtained in pure form by high performance liquid chromatography (HPLC) of dithiothreitol- and iodoacetamide-treated SF-R. Only the beta chain bound SF.
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PMID:Identification and purification of a receptor on macrophages for the dengue virus-induced suppressor cytokine. 838 39


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