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Biomedical subjects

P D Weston

Publications and source records attributed to P D Weston.

11 recordsLinked to original sources
PubMed1983

A new reagent which may be used to introduce sulfhydryl groups into proteins, and its use in the preparation of conjugates for immunoassay.

A synthesis of the N-hydroxysuccinimide ester of S-acetylthioacetic acid is described. This material is stable when stored dry and has advantages over the currently available reagents used to introduce sulfhydryl groups into a variety of proteins. Proteins modified with this reagent can be used to prepare conjugates for enzyme immunoassay. The conjugation techniques described cause little or no loss of either enzyme activity or antibody titer and function, and the conjugates contain little polymeric material.

Acetylation↗
PubMed1982

Activation of beta-galactosidase by monoclonal antibodies.

Four monoclonal cell lines secreting antibodies that activate the beta-galactosidase protein from lac-aba strains of Escherichia coli have been isolated. One of the antibodies, BG 79, inhibits the normal beta-galactosidase from E. coli in addition to its activation of the protein from mutants. Moreover, when in combination with any of the other activating antibodies, BG 79 exhibits synergistic activation of the beta-galactosidase protein, and the synergistically activated enzyme is stimulated by methanol, although most of the proteins activated by single antibodies are inhibited by methanol. The equilibrium of binding of BG 79 to the beta-galactosidase protein is not affected by the presence of a second antibody, and the half-time for activation by BG 79 is only slightly, though significantly, increased by preincubation of the protein with the second antibody. Our results imply that activation of beta-galactosidase proteins is not a simple correction of a conformational defect, and that many distinct active conformations are available to the enzyme.

Antibodies, Monoclonal↗
PubMed1980

Conjugation of enzymes to immunoglobulins using dimaleimides.

A method is described for coupling enzymes to immunoglobulins using sulphydryl derivatives of the proteins and a dimaleimide which is relatively water-soluble. Parameters affecting the performance of the conjugates have been examined including level of sulphydryl incorporation, ratio of enzyme/immunoglobulin and nature of dimaleimide used. Peroxidase-immunoglobulin conjugates made by the dimaleimide method have been compared with those made by the periodate oxidation method and found to have a superior performance. Immunoglobulin has been linked to peroxidase (horseradish peroxidase, EC 1.11.1.7), glucose oxidase from Aspergillus niger, (EC 1.1.3.4), penicillinase from Bacillus cereus beta-lactamase I (EC 3.5.2.6), and beta-galactosidase from Escherichia coli (EC 3.2.1.23).

Immunoenzyme Techniques↗
PubMed1971

Cathepsin D. Characteristics of immunoinhibition and the confirmation of a role in cartilage breakdown.

1. Antisera were raised against lysosomal cathepsin D of man, chicken and rabbit. 2. The antisera were found to be specific and potent inhibitors of cathepsin D activity. 3. The immunological nature of the inhibition was established. 4. The inhibitory effect was studied by varying pH, antiserum/enzyme ratio, time of incubation, concentration of components and order of mixing, and by using purified antibody and univalent antibody fragments. 5. The specificities of the antisera were examined with respect to other enzymes, isoenzymes of cathepsin D and cathepsin D from different organs. 6. The antisera prevented the action of cathepsin D on isolated proteoglycans and on cartilage. 7. The antisera produced up to 90% inhibition of the autolysis of cartilage from chicks and rabbits, indicating that cathepsin D is the enzyme mainly responsible for the breakdown of proteoglycans in this system.

Animals↗
PubMed1966

The effect of normal development and of severe undernutrition on some minor components of cortical bone.

1. The amounts of calcium, magnesium, sodium and citric acid in the bones of undernourished pigs 1 year old were compared with the amounts in the bones of smaller newborn animals, normal animals of the same weight aged 4 weeks and of the same age weighing 170kg. 2. The differences that were found between 4 weeks and 1 year of age in the normal animals were expected as effects of aging. However, between birth and 4 weeks of age the changes in composition were in the opposite direction to those between 4 weeks and 1 year. 3. Undernutrition produced a bone that resembled chemically that of an animal 1 year old.

Animals↗