Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PAPAIN”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources
PubMed1984

Human monoclonal cryoimmunoglobulins. I. Molecular properties of IgG3 kappa (Jir protein) and the cryo-coprecipitability of its molecular fragments by papain.

The temperature-dependent precipitability of a monoclonal IgG3 kappa cryoimmunoglobulin (Jir) without known antibody activity is shown to be affected by various physico-chemical factors, such as protein concentration, pH value and NaCl concentration. The molecular properties characterizing this protein (carbohydrate and amino acid compositions, peptide constitutions and susceptibility to enzymatic proteolysis) are described. The cryoprecipitability of the protein was completely lost upon papain hydrolysis, and none of the isolated fragments, Fab-Fc, Fc, and Fab, showed any precipitating activity. In the cryo-coprecipitation assay using the 125I-labeled fragments, it was demonstrated that the association activity with intact Jir protein was still retained on the Fab-Fc and Fc fragments, but not on the Fab fragment. The evidence suggests that a specific interaction may be involved in the primary intermolecular association required to form the cryoprecipitate at temperatures below the critical point, and that one of the pairing sites resides on the Fc portion of the protein molecule.

Amino Acids↗
PubMed2003

Processing and subcellular localization of the leader papain-like proteinase of Beet yellows closterovirus.

ORF 1a of Beet yellows closterovirus (BYV) encodes the domains of the papain-like proteinase (PCP), methyltransferase (MT) and RNA helicase. BYV cDNA inserts encoding the PCP-MT region were cloned in pGEX vectors next to the glutathione S-transferase gene (GST). In a 'double tag' construct, the GST-PCP-MT cDNA was flanked by the 3'-terminal six histidine triplets. Following expression in E. coli, the fusion proteins were specifically self-cleaved into the GST-PCP and MT fragments. MT-His(6) was purified on Ni-NTA agarose and its N-terminal sequence determined by Edman degradation as GVEEEA, thus providing direct evidence for the Gly(588)/Gly(589) bond cleavage. The GST-PCP fragment purified on glutathione S-agarose was used as an immunogen to produce anti-PCP monoclonal antibodies (mAbs). On Western blots of proteins from virus-infected Tetragonia expansa, the mAbs recognized the 66 kDa protein. Immunogold labelling of BYV-infected tissue clearly indicated association of the PCP with the BYV-induced membranous vesicle aggregates, structures related to closterovirus replication.

Aizoaceae↗
PubMed2006

A Phytophthora infestans cystatin-like protein targets a novel tomato papain-like apoplastic protease.

There is emerging evidence that the proteolytic machinery of plants plays important roles in defense against pathogens. The oomycete pathogen Phytophthora infestans, the agent of the devastating late blight disease of tomato (Lycopersicon esculentum) and potato (Solanum tuberosum), has evolved an arsenal of protease inhibitors to overcome the action of host proteases. Previously, we described a family of 14 Kazal-like extracellular serine protease inhibitors from P. infestans. Among these, EPI1 and EPI10 bind and inhibit the pathogenesis-related (PR) P69B subtilisin-like serine protease of tomato. Here, we describe EPIC1 to EPIC4, a new family of P. infestans secreted proteins with similarity to cystatin-like protease inhibitor domains. Among these, the epiC1 and epiC2 genes lacked orthologs in Phytophthora sojae and Phytophthora ramorum, were relatively fast-evolving within P. infestans, and were up-regulated during infection of tomato, suggesting a role during P. infestans-host interactions. Biochemical functional analyses revealed that EPIC2B interacts with and inhibits a novel papain-like extracellular cysteine protease, termed Phytophthora Inhibited Protease 1 (PIP1). Characterization of PIP1 revealed that it is a PR protein closely related to Rcr3, a tomato apoplastic cysteine protease that functions in fungal resistance. Altogether, this and earlier studies suggest that interplay between host proteases of diverse catalytic families and pathogen inhibitors is a general defense-counterdefense process in plant-pathogen interactions.

Algal Proteins↗
PubMed1992

The segmented anisotropic refinement of monoclinic papain by the application of the rigid-body TLS model and comparison to bovine ribonuclease A.

The anisotropic displacements of selected rigid groups in monoclinic papain have been refined from X-ray diffraction data by application of the rigid-body TLS model. The rigid groups chosen were the aromatic side chains of tryptophan, tyrosine, histidine and phenylalanine, and the planar carboxylic and guanidinium side chains of aspartic acid, glutamic acid, glutamine, asparagine and arginine. The derived translation and libration tensors have been compared with those previously derived for bovine ribonuclease A and provide evidence for different modes and anisotropies of displacement over the two proteins.

Amino Acids↗
PubMed1993

Interaction of papain-digested HLA class I molecules with human alloreactive cytotoxic T lymphocytes (CTL).

Acute immunological rejection events of transplanted allogeneic organs are strongly dependent on T cell reactivity against foreign MHC products. The recognition requirements of alloreactive cytotoxic T cells are of particular interest for finding approaches to modulating alloreactivity. The role of the allogeneic MHC molecule itself and/or an associated peptide in the interaction with the T cell receptor is still, however, unclear. Our studies have focused on the interactions of papain-digested HLA class I molecules with alloreactive CD8+ CTL. These polypeptides, consisting of the polymorphic alpha 1 and alpha 2 and the monomorphic alpha 3 domains, were used in both soluble and immobilized form to study their functional effects on anti-HLA-A2 reactive CTL. Purified polypeptides were of molecular mass 32-34 kD. HLA-A2 polypeptides (0.55 micrograms/ml) in soluble form induced half-maximal reduction of CTL cytotoxicity. These concentrations were quantitatively comparable to the effective doses of intact HLA class I molecules, which contain the hydrophobic transmembrane domain and the intracytoplasmic tail. In addition, specific activation requirements of these CTL were investigated in a serine esterase release assay. Maximal degranulation was observed after 2 h of antigen contact. Purified HLA class I molecules allospecifically activated the anti-HLA-A2 CTL to degranulate serine esterase, when immobilized on plastic microtitre plates. Thus, polypeptides containing the polymorphic alpha 1 and alpha 2 domains of human class I molecules potentially modulate the cytotoxic T cell response. This might have implications for the reduction or prevention of allograft rejection in recipients of foreign organs.

Cytotoxicity, Immunologic↗
PubMed1979

Primary structure of pooled, papain-solubilized HLA-A, -B, and -C antigens.

The tentative amino acid sequence of pooled, papain-solubilized HLA antigen heavy chains has been determined. The amino acid sequence comprises 273 residues. As the structural analyses were performed on HLA antigen heavy chains comprising a mixture of several allelic forms derived from the A, B, and possibly C loci, multiple residues were encountered in several positions. However, a quantitatively dominating residue could always be easily identified. The present data suggest that the amino acid variability of the HLA-A, -B, and -C antigens is found in restricted regions of the molecule. The COOH-terminal third of the HLA antigen heavy chain appears to be less variable than other regions of the molecule. Previous work has shown that the HLA antigen heavy chain contains two immunoglobulin-like disulphide loops. The COOH-terminal third of the heavy chain was shown to be similar in primary structure to beta 2-microglobulin and the immunoglobulin G constant domains.

Amino Acid Sequence↗
PubMed1980

Properties of purified papain-solubilized rat AgB antigens and reactivity of a xenoantiserum against the isolated antigens.

Rat AgB transplantation antigens were isolated after papain digestion of spleens from the inbred strain Hooded Lister. Both subunits of the AgB antigens were present in the purified material. Some physical characteristics of the antigens have been determined. An antiserum, raised in a rabbit, against the purified material reacted exclusively with AgB antigens on splenocytes but detected novel structures on both adult and embryonic fibroblasts. These structures, antigenically related to AgB antigens, were not detected on plasmacytoma or hepatoma cells, nor did they display any antigenic similarity with rat beta 2-microglobulin. Radioimmunoassays specific for the AgB antigen heavy chain and for beta 2-microglobulin, respectively, were used to estimate the contents of these antigens in several tissues. Spleen and thymus exhibit the largest density, while brain is almost devoid of these antigens.

Animals↗
PubMed1984

Peptide synthesis catalyzed by papain at alkaline pH values.

The synthesis of peptides in the presence of papain at pH 8-9.5 is described. Starting substances are acylamino acid alkyl esters (the carboxyl component) and amides or tert.-butylesters of amino acids, as well as peptide (the amino component). Under such conditions secondary hydrolysis is not essential, making the synthesis of peptides soluble in aqueous medium. The yield of peptides is 50-94%. The effect of different factors (temperature, solvents, reagent concentrations) on the result of the reaction has been studied. It has been found that an excess of the carboxyl component is expedient to increase the yield of peptides.

Hydrogen-Ion Concentration↗
PubMed1978

The use of low ionic strength solution (LISS) in elution experiments and in combination with papain-treated cells for the titration of various antibodies, including eluted antibody.

The investigation presents evidence for the value of suspending red cells in a low ionic strength medium for elution experiments since this has the effect of increasing the uptake of antibodies by the red cells. In addition it has been shown that for the titration of low affinity antibodies, and also of eluted antibodies, the combining capacity of which may be impaired through the elution process, it is an advantage to use a LISS-enzyme (papain) technique.

Antigen-Antibody Reactions↗
PubMed1984

Hemagglutination and the closest distance of approach of normal, neuraminidase- and papain-treated erythrocytes.

By means of potential energy versus distance diagrams, derived from electrophoretic and surface tension data, the minimum distances of approach of normal (NOR) and of neuraminidase-treated (NEU) and papain-treated (PAP) human erythrocytes could be determined. The minimum distances between the actual cell membranes of two opposing red cells are: 184 A (NOR), 111 A (NEU), and 113 A (PAP), which agrees well with the fact that anti-D (Rho) antibodies of the IgG-class (which have a maximum distance of approximately 120 A between the two antibody-active sites) can hemagglutinate NEU and PAP cells, but are incapable of hemagglutinating normal D (Rho)-positive erythrocytes.

Antigen-Antibody Reactions↗
PubMed1986

Active-site ionizations of papain. An evaluation of the potentiometric difference titration method.

The underlying assumption of the potentiometric difference titration method, as applied to the evaluation of the sulfhydryl-dependent ionizations in the active site of papain, is that the pKa of His-159 is independent of whether the neighboring sulfhydryl (Cys-25) is protonated or methylthiolated. That this idealized assumption may not strictly apply is indirectly indicated by the larger pKa of His-159 in S-methylpapain versus that in S-methylthiopapain, as determined from fluorometric titrations (delta pKa = 0.32 +/- 0.05, 25 degrees C). On the basis of the Wegscheider principle of the equivalence of protons and methyl groups, the potentiometric difference titration method will underestimate the concentration of thiolate-imidazolium ion pair in the active site versus that of the thiol-imidazole tautomer, provided that there is no significant H-bonding interaction in the latter species.

Binding Sites↗
PubMed1991

Cellobiose oxidase from Phanerochaete chrysosporium can be cleaved by papain into two domains.

Cellobiose oxidase from the white rot fungus Phanerochaete chrysosporium has been purified to homogeneity by a new method. The enzyme has been cleaved by papain into two fragments: one containing the heme group and one containing the flavin group. The flavin fragment can oxidize cellobiose and is reoxidized by oxygen. Cellobiose oxidase binds to cellulose to approximately the same extent as cellobiohydrolase I. The cellulose-binding site is located on the flavin domain. The enzyme cannot be totally displaced from cellulose by cellobiose, and it is still active when adsorbed to cellulose. The possible role of the enzyme in lignocellulose degradation is discussed.

Amino Acids↗
PubMed1982

Inhibition of trypsin and papain by sodium aurothiomalate mediated by exchange reactions.

Sodium aurothiomalate has been shown to participate in exchange reactions leading to the inhibition of trypsin; for this exchange to take place it was necessary to include in the test system a suitable thiol, such as N-acetyl-cysteine. Neither N-acetyl-cysteine nor aurothiomalate on their own had any inhibitory action on trypsin. The results indicate that aurothiomalate dissociates in the presence of a carrier to form thiosuccinate and gold. The gold is responsible for trypsin inhibition since independent experiments demonstrated that the total concentration of thiosuccinate was insufficient to cause the observed inhibition of trypsin. Bovine serum albumin was shown to act as a carrier in place of N-acetyl-cysteine. It is known that histidine in the active centre of trypsin binds heavy metal ions with consequent inhibition of the enzyme. In this study, imidazole was shown to act as a carrier for gold from aurothiomalate to trypsin resulting in inhibition. This inhibition by gold was reversed when higher concentrations of imidazole were added to the test system due to competition for the trypsin-bound gold by imidazole. Conversely, the thiol enzyme papain was re-activated in the presence of low concentrations of sodium aurothiomalate and inhibited by higher concentrations of this reagent in a biphasic manner. This observation will be discussed in relation to the dissociation of sodium aurothiomalate. These observations can also be explained in terms of exchange reactions involving thiols and free metal ions.

Acetylcysteine↗
PubMed1988

The 43 kDa papain inhibitor in normal and diseased skin.

The presence of 43 kDa papain inhibitor in 43 different skin diseases was immunohistochemically studied by using both poly- and monoclonal antibodies. Psoriasis and various eczematoid reactions as well as viral infections showed the most pronounced staining in the squamous cells of the epidermis. The antigen was also present in benign tumours or precancerous lesions which showed keratinization. Cells of poorly differentiated squamous cell carcinomas, basal cell carcinomas and melanocytic tumours were negative. The antigen seems to be related to disturbed keratinization and benign proliferation in non-neoplastic dermatoses and it is also present in differentiating squamous neoplasms.

Antibodies↗
PubMed1984

Analysis of the immune response to papain digestion products of tetanus toxin.

Tetanus toxin was degraded by papain and the previously characterized Fragment B and Fragment C were isolated. The induction of protective immunity against tetanus toxin was subsequently investigated in two animal models using Fragment B and Fragment C, as well as conventional tetanus toxoid for comparison. In guinea pigs, Fragment B showed an immunizing potency similar to that recorded for an equal amount of tetanus toxoid, whereas Fragment C was considerably less efficient, on an equal weight basis. In contrast, mice immunized with Fragment C reached a protection level similar to that achieved after immunization with the complete tetanus toxoid antigen. In both animal models, Fragments B and C acted in a synergistic fashion when injected together. Analysis of sera from guinea pigs using ELISA, after administration of a low dose of tetanus immunogen corroborated these results. The data indicate that antigenic determinants in distinct regions of the toxin molecule independently may induce antibodies neutralizing the lethal action of tetanus toxin. The immune response to the complete toxoid antigen may be subject to influence by intramolecular competition between antigenic determinants. The immunogenicity of the fragments as measured by the protection rate after active immunization may depend upon the animal species used.

Animals↗
PubMed1989

Immunological characterization of papain-induced fragments of Clostridium botulinum type A neurotoxin and interaction of the fragments with brain synaptosomes.

After treatment of Clostridium botulinum type A neurotoxin with papain, three fragments (Mrs, 101,000, 45,000, and 43,000) were purified by hydrophobic and ion-exchange chromatography with a high-performance liquid chromatographic system. Immunoblotting analyses with monoclonal antibodies showed that the 101,000-dalton fragment consisted of the light chain and a part of the heavy chain (H-1 fragment) linked together by a disulfide bond, and the other two fragments were correlated to the remaining portion of the heavy chain (H-2 fragment). The 45,000- and 43,000-dalton fragments effectively competed for binding of the 125I-labeled neurotoxin to synaptosomes, while no inhibition was observed with the 101,000-dalton fragment. The results indicate that the H-2 fragment interacts with the binding site on the neural membrane. The binding of the neurotoxin was impaired by treatment of synaptosomes with neuraminidase. Incorporation of gangliosides into neuraminidase-treated synaptosomes resulted in the restoration of binding. The results suggest that gangliosides are one of the components of the toxin-binding site.

Animals↗
PubMed1993

Papain-like protease p29 as a symptom determinant encoded by a hypovirulence-associated virus of the chestnut blight fungus.

Viral double-stranded RNAs (dsRNAs) responsible for virulence attenuation (hypovirulence) of the chestnut blight fungus, Cryphonectria parasitica, profoundly influence a range of host functions in addition to virulence. The 5'-proximal open reading frame, A, of the prototypical hypovirulence-associated viral dsRNA, L-dsRNA, present in hypovirulent strain EP713, was recently shown by DNA-mediated transformation analysis to suppress fungal sporulation, pigmentation, and accumulation of the enzyme laccase (G. H. Choi and D. L. Nuss, EMBO J. 11:473-477, 1992). We mapped this suppressive activity to the autocatalytic papain-like protease, p29, present within the amino-terminal portion of open reading frame A-encoded polyprotein p69. Mutational analysis revealed that the ability of p29 to alter fungal phenotype is dependent upon release from the polyprotein precursor but is independent of intrinsic proteolytic activity. Deletion of the p29-coding domain within the context of an infectious L-dsRNA cDNA clone resulted in a replication-competent viral dsRNA that exhibited intermediate suppressive activity while retaining the ability to confer hypovirulence. Thus, p29 is necessary but not sufficient for the level of virus-mediated suppression of fungal pigmentation, sporulation, and laccase accumulation observed for wild-type hypovirulent strain EP713 and is nonessential for viral RNA replication and virulence attenuation. These results also illustrate the feasibility of engineering infectious viral cDNA for construction of hypovirulent fungal strains with specific phenotypic traits.

Amino Acid Sequence↗