Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Properties of a proline-rich polypeptide (PRP) accompanying ovine colostral IgG2 are described. PRP is soluble at 4 degrees C but reversibly precipitates by warming to room temperature. Maximal precipitation is observed at pH = 4.6, temp. 48 degrees C, and ionic strength higher than 0.6. There is a linear dependence of precipitation on concentration of PRP. Molecular weight of PRP is 38,000 daltons. It is not changed in the presence of 6 M guanidine hydrochloride, SH-compounds, and in the presence or absence of metal ions. PRP is built of one polypeptide chain. No difference in proteolysis of IgG2 by pepsin, papain and trypsin in the absence or presence of PRP was found.
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PMID:Physicochemical properties of a proline-rich polypeptide (PRP) from ovine colostrum. 3 26

The human alloantigenic specificities w4 and w6, which are products of a diallelic system genetically associated with the HLA-B locus, have been solubilized by papain digestion of membranes from the lymphoblastoid cell line, RPMI 4265. The w4 and w6 specificities copurified with the HLA-B locus products, HLA-B7 and HLA-B12. Sequential immunoprecipitation experiments were performed using alloantisera to HLA-B7, HLA-B12, w4 and w6, and a purified HLA-B7, B12, w4, w6 antigen pool labeled with 125I-Bolton-Hunter reagent. These experiments demonstrated directly that HLA-B7 and w6, which are genetically associated with each other, are different antigenic determinants on the same molecule, while HLA-B12 and w4, also genetically associated, are distinct antigenic determinants on a second molecule. Arguments are presented which suggest that the HLA-B determinants and w4, w6 determinants are in fact on the same polypeptide, and the genetic implications of the findings are discussed.
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PMID:HLA-B specificities and w4, w6 specificities are on the same polypeptide. 6 73

The interaction between tetanus toxin and ganglioside containing 2 N-acetylneuraminic acid residues linked in sequence to one another has been investigated using a new method involving radioactively labeled ganglioside and tetanus toxin adsorbed to Sephadex matrix. Binding between the two components was demonstrated, and it was calculated that in the nanomolar concentration range, tetanus toxin becomes half-saturated at about 5 X 10(-8) M concentration of ganglioside. Removal of the ceramide portion from the ganglioside resulted in the complete loss of binding activity, whereas removal of the terminal N-acetylneuraminic acid residue from the intact ganglioside had no effect. Among the fragments derived from tetanus toxin (Helting, T. B., and Zwisler, O. (1977) J. Biol. Chem. 252, 187-193), only the heavy chain polypeptide exhibited a binding activity of the same order of magnitude as that observed for the native toxin. The light chain polypeptide showed no interaction with ganglioside and among the fragments derived from the toxin by digestion with papain, only Fragment C, at a high protein concentration, displayed marginal binding activity. Using monovalent antibodies directed against specific regions of the tetanus toxin molecule, it was demonstrated that antibodies directed against Fragment C uniquely interfere with the binding process. Anti-light chain serum was ineffective, as well as antitetanus toxoid serum previously absorbed with Fragment C. It is concluded that the binding site for ganglioside is located on the heavy chain portion of tetanus toxin, possibly in or near the region comprised by Fragment C.
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PMID:Structure of tetanus toxin. II. Toxin binding to ganglioside. 6 69

A rabbit antiserum raised against highly purified, papain-solubilized H-2d antigens contained two sets of non-crossreacting antibodies directed against each one of the two H-2 antigen subunits. The antiserum recognized only 12,000 and 47,000 dalton polypeptide chains when splenocyte membrane glycoproteins were analysed. Among the molecules precipitated with the rabbit antiserum all H-2K and D antigens were present. In addition to regular H-2K and D antigens minor amounts of material with the typical H-2 antigen subnit structure, but lacking alloantigenic determinants, were precipitated by the antiserum. These 'non-H-2 antigens' were produced in relatively greater amounts by T-cells than by B-cells. Both sets of antibodies in the rabbit antiserum reacted with the TL antigens demonstrating that there is an immunological crossreactivity between the classical alloantigenic H-2 antigen chain and the alloantigenic TL antigen chain. The F9 cell line, believed to represent cells at the morula stage, display H-2 antigen-like structures as revealed by the rabbit antiserum.
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PMID:Reactions and crossreactions of a rabbit anti-H2 antigen serum. 7 53

A complex of inflammatory protease with an inhibitor was found to be present in the early phase of Arthus skin lesions in guinea pig. From the extract of inflamed lesions a complex was partially purified by chromatography on DEAE-Sephadex A-50 and GE-cellulose, in that order. The inhibitor was finally dissociated rom the protease complex by treating them with cysteine followed by Sephadex G-50 chromatography. Active protease was recovered as a single peak which also contained some inhibitor activity. The isolated inhibitor was capable of inactivating inflammatory protease as well as papain. It was electrophoretically homogenous and was identified as protein or polypeptide in the serum alpha-1-globulin fraction. The significant role of the inhibitor in regulating the acute phase of inflammatory process is emphasized.
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PMID:Studies on the role of proteases in the biochemical mechanisms of tissue injury. 12 91

Heavy meromyosin subfragment-1 (HMM S-1) was prepared by papain digestion of arterial myosin or actomyosin and was purified by agarose-ATP affinity chromatography. Proteolysis of crude arterial myosin suspensions was preceded by solubilization. HMM-S-1 thus obtained consisted mainly of a 90,000 dalton polypeptide and fully retained the K+- and Ca2+-ATPase of the parent myosin. Its affinity to agarose-ATP was comparable to that of skeletal muscle HMM S-1.
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PMID:Affinity chromatographic preparation of arterial heavy meromyosin subfragment-1. 13 7

Both F(ab')2 fragments and intact antibody from rabbit anti-B-cell antisera were shown to specifically block the mixed lymphocyte culture (MLC) reaction. The antisera, which were raised to papain-solubilized spleen cell membrane antigens, appeared to block the stimulator cell and not the responder cell. Specificity of the blocking was shown in that antisera to beta2 microglobulin would not block the MLC-stimulating cell. Membrane antigens from acute lymphocytic leukemia cells were labeled with 125I, solubilized with sodium deoxycholate and immunoprecipitated with either human or rabbit anti-B-cell antisera. Both sources of antisera precipitated polypeptide subunits of 27,000 and 35,000 daltons.
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PMID:Two-chain subunit structure of HLA-D antigens. 14 35

The LAF produced by the mouse macrophage cell line, P388D1, is a single polypeptide chain of m.w. 12,000 to 16,000 daltons. Native LAF was destroyed by Streptomyces griseus protease, but not by trypsin, chymotrypsin, and papain, although in the presence of 8 M urea, papain completely destroyed LAF activity. LAF did not bind to concanavalin A-Sepharose, suggesting that LAF does not contain significant amounts of mannosyl or glycosyl residues. Since LAF activity was not inactivated by a treatment of reduction and alkylation the active conformation of LAF does not appear to be dependent on disulfide linkages. LAF was not irreversibly denatured by 8 M urea or 0.1 to 0.5% SDS. On SDS-polyacrylamide gels, the m.w. of LAF was 12,000 daltons, as compared to a value of 16,000 daltons, as determined by gel filtration. The isoelectric point of LAF was 5.0 to 5.4 as determined on 7.5% acrylamide gels (pH 3 to 10). On the basis of these results it appears that the P388D1 cell line-derived LAF is a relatively stable molecule that shares several physicochemical properties with normal human and mouse macrophage-derived LAF.
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PMID:Physicochemical characterization of lymphocyte-activating factor (LAF). 31 60

Tetanus toxin was digested with papain, yielding one major polypeptide (Fragment C) with a molecular weight corresponding to 47,000 +/- 5%, thus comprising about one-third of the toxin molecule. Fragment C was antigenically active, atoxic, and stimulated the formation of antibodies neutralizing the lethal action of tetanus toxin in vivo. Furthermore, a second split product (Fragment B) was isolated from the papain digest, containing two polypeptide chains linked together via a disulfide bond. Fragment B (Mr = 95,000 +/- 5%) was atoxic and showed a reaction of nonidentity with Fragment C on immunodiffusion analysis against tetanus antitoxin. The basic two-chain structure (heavy and light chain polypeptide, cf. Matsuda, M., and Yoneda, M. (1975) Infect. Immun. 12, 1147-1153) of tetanus toxin has been confirmed and the relationship between Fragments B and C within this framework has been established. Fragment C was distinguished from the light chain by electrophoresis in sodium dodecyl sulfate and by immunodiffusion analysis, indicating that this fragment constitutes a portion of the heavy chain polypeptide. Fragment B showed a reaction of partial identity with the light as well as the heavy chain from tetanus toxin. Reduction of Fragment B with dithiothreitol followed by gel chromatography yielded a fraction which was indistinguishable from the light chain portion of the toxin molecule. It is concluded that Fragment B comprises the complementary portion of the heavy chain (remaining after scission of the polypeptide bond(s) releasing Fragment C) linked to the light chain by a disulfide bond.
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PMID:Structure of tetanus toxin. I. Breakdown of the toxin molecule and discrimination between polypeptide fragments. 40 8

Prolonged papain digestion of rat IgG2a produced two molecular species of Fc fragments, termed Fc(I) and Fc(II). Studies by gel filtration chromatography and polyacrylamide gel electrophoresis in SDS/urea indicated that the two subunit polypeptide chains in each Fc preparation were associated by non-covalent bonds only. By analytical ultracentrifugation Fc(I) was found to have a m.w. of 47,100 and a sedimentation coefficient of 4.08S. Fc(II) had a m.w. of 39,800 and a sedimentation coefficient of 3.83S. The m.w. for the subunit chains of Fc(I) and Fc(II) were 25,300 and 20,300, respectively, as determined by analytical ultracentrifugation under dissociating conditions. Calculation of the frictional coefficient ratios indicated that both Fc fragments possessed compact globular structures. The difference in size between these two Fc fragments probably was due to a loss of some carboxy-terminal residues in Fc(II). Both Fc fragments possessed nearly identical amino-terminal amino acid sequences. Papain cleavage occurred primarily between residues 233/234 and 234/235. The carbohydrate compositions of the two species of Fc fragments were similar. It was concluded that under acid and reducing conditions papain cleavage of rat IgG2a occurred to the carboxy-terminal side of the hinge region. Prolonged papain digestion led to secondary attack in the carboxy-terminal end of the CGAMMA3 domain at an unidentified site, or sites, producing a stable second species of Fc fragments.
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PMID:Characterization of two species of Fc fragments obtained from rat IgG2a by prolonged papain digestion. 40 15


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