Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Trypanosoma rangeli-secreted sialidase was purified by bovine submaxillary gland mucin-sepharose affinity chromatography. In immunoblotting analysis, antibodies raised against this molecule recognized polypeptides of 73 kDa in T. rangeli medium supernatant (TrSialr) and of 70 kDa in the cell lysates of T. rangeli (TrSials) and T. cruzi (TcSialL) epimastigotes. TrSialr, TrSials, and TcSialL were subjected to proteolytic cleavage with papain; the resultant peptide pattern displayed differences in the immunoblotting profiles. TrSials was purified by immunoprecipitation, and this protein band was recognized by sera from T. cruzi-infected chronic mice and Chagas' disease patients. In contrast, TrSialr was not recognized by these sera. The antibodies from the infected mice also recognized a band of 70 kDa present in the medium. These preliminary observations imply that the released and somatic sialidases are partially different molecules, with probably different biological roles. The related proteins recognized in T. rangeli and T. cruzi epimastigotes share many antigenic characteristics but have some structural differences, probably related to their function in the parasitic cell. On the basis of the strong antigenicity of TrSials, this molecule is proposed as the antigen for the detection of antibodies arising during T. cruzi infection.
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PMID:Antigenic significance of a Trypanosoma rangeli sialidase. 1219 16

Adult Aplysia gonad contains high levels of a galactophilic lectin (MW around 65 kDa; composed of 2 subunits of apparent single species). It binds galactose and various alpha/beta-galactosides (but not N-acetylgalactosamine), in addition to an outstanding high affinity for galacturonic acid. This lectin is relatively resistant to heating up to 70 degrees C and to alkaline pH, but sensitive to proteolysis and low pH. It resembles galectins in binding to poly LacNAc (preferentially branched) complexes at low temperatures (0 degrees-4 degrees C) more avidly than at room temperature or at 37 degrees C, but differs from them in being Ca(2+)-dependent. It agglutinates papain/sialidase-treated erythrocytes more strongly than untreated cells and stimulates mitosis in peripheral human lymphocytes (inducing IL-2 formation). This lectin also enhances neurite outgrowth and increases their viability, while suppressing cell tumorigenicity. It is useful for histochemical/ cytochemical studies of galacturonic acid in plant tissues and fungi and for the study of cell surface composition of various prokaryotic (including halophilic Archaea) and eukaryotic cells and for their typing. It is useful as a reagent for I-antigen detection in adult human erythrocytes (anti-I), exhibiting strongest agglutination of O(h) Bombay-type erythrocytes and also exhibits sensitivity to the T antigen. It binds galactosylated molecules in human body fluids (shown by hemagglutination--inhibition tests), including saliva, seminal fluid and milk (detecting individual divergence) and in fowl egg albumens (exhibiting highest affinity for that of pigeon). Therefore, it might be valuable as a probe and fishhook for fishing compounds exhibiting anti-bacterial/neoplastic cell adhesion activities.
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PMID:Binding properties and applications of Aplysia gonad lectin. 1453 93

While studying the serologic characteristics of certain monoclonal blood group antibodies, we observed a hybridoma clone (5A-11E10) with anti-N-like serologic specificity that was dependent on the presence of the bicarbonate anion. The diluted cell culture supernatant preferentially agglutinated M-N+ RBCs by immediate spin. This supernatant also agglutinated M-N+ RBCs that had been treated with trypsin or sialidase (to remove N-reactivity), suggesting anti-'N' activity. Anti-'N' specificity was confirmed by the supernatant's non-reactivity with N+ RBCs treated with papain (to remove 'N' reactivity) or with ('N'-negative) M+N-U- RBCs. The requirement for bicarbonate in the MoAb's formulation was not a function of pH. Both sodium and ammonium bicarbonate supported agglutination, but neither sulfate nor carbonate was effective.
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PMID:A bicarbonate anion-dependent anti-'N' MoAb. 1537 70

Enzyme or chemical modification of intact red cells results in the destruction of some blood group antigens. The pattern of reactions of an antibody with red cells treated with various proteinases, with sialidase, and with the disulfide bond-reducing agent 2-aminoethylisothiouronium bromide (AET) can aid in antibody identification. This information can prove particularly beneficial with antibodies to antigens of very high frequency, where antigen- negative cells may be difficult to obtain. Provided in this article is a table listing most of the authenticated high-frequency red cell antigens and the effect on those antigens of trypsin, chymotrypsin, a mixture of trypsin and chymotrypsin, papain, pronase, sialidase, and AET.
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PMID:Effect of enzymes on and chemical modifications of high-frequency red cell antigens. 1594 59

Cross-reactivities of monoclonal reagents for red blood cell (RBC) typing are seen very rarely, e.g. in some reagents for testing of ABO or Lewis antigens. We report on two patients in whom we observed weak reactions using a monoclonal anti-c reagent containing clone MS35, but no reactions with anti-c reagents containing other monoclonal or polyclonal antibodies. To resolve this discrepancy, we studied RHCE exon 1 (Ex1) and 2 from genomic DNA of one patient and performed quality controls of the false-positive reacting anti-c reagent. RHCE Ex1 showed no abnormalities as well as RH Ex2 examined with primers specific for Ex2 D/C. No amplification product of RH Ex2 was received with primers specific for c. A titration study with untreated, papain-treated and sialidase-treated adult and newborn RBCs showed anti-i reactivity of the false-positive reacting reagent. This reactivity could not be removed by absorption with c-negative newborn RBCs without reducing the anti-c titre in the same way, indicating a cross-reactivity. Some manufacturers give a remark on a possible cold agglutinin activity of their monoclonal anti-c reagents in the instruction leaflet, but in order to avoid such irritation, we recommend to remove this cross-reactivity by dilution during the manufacturing process.
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PMID:False-positive reactions of some monoclonal anti-c reagents. 1956 72


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