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Biomedical subjects

S M Partridge

Publications and source records attributed to S M Partridge.

At least 19 recordsLinked to original sources
PubMed1982

Immunological studies with human aortic elastin.

Antibodies to human fetal aortic elastin were isolated from sheep immunized with alpha-elastin peptides. In preliminary tests of specificity using passive hemagglutination, partial cross-reactivity was demonstrated with alpha-elastin from other species. However, in a double antibody radio-immunoassay alpha-elastin peptides from other mammalian species failed to compete with 125I-labelled human alpha elastin. These results suggest the existence of at least two different antigenic sites on the elastin molecule. One, a high affinity site, demonstrates species specificity at low antigen/antibody concentrations. The other, a low affinity site, is common to mammalian elastins and is demonstrated at high antibody/antigen concentrations. In the radioimmunoassay the antibodies showed considerably less avidity for adult human alpha-elastin than for the fetal antigen. This implies that the species specific site is age-dependent and probably involves the cross-linking region of the elastin molecule. Using the sheep antiserum immunohistochemical staining of elastic tissue has been developed. This should prove to be a useful technique for studying polymeric elastin in intact tissue by light microscopy and at the ultrastructural level.

Adult↗
PubMed1979

Molecular weights and Stokes radii of soluble elastins.

Soluble elastin was isolated from lathyritic chick aorta using neutral salt solutions in the presence of beta-amino propionitrile. The effect of a carboxy-methylation step in conjunction with proteolytic inhibitors was investigated. Hydrodynamic (Stokes) radii of soluble elastins were measured by gel filtration and the molecular size and weight distribution in purified fractions are reported.

Amino Acids↗
PubMed1977

The coacervate-sol transition observed with alpha-elastin and its N-formyl O-methyl derivative.

The coacervate phase produced by raising the temperature of solutions of blocked alpha-elastin has water content and fibrillar structure at electron microscope level similar to fibrous elastin (Cox, B.A., Starcher, B.C., Urry, D.W. (1973) Biochim, Biophys. Acta 317, 209-213). The stability ranges of the coacervates under varying conditions of temperature, pH, salt concentration and concentration of added organic solvent have been investigated with results that suggest a marked sensitivity of elastin conformation to solution conditions.

Elastin↗
PubMed1976

Purification and properties of the extracellular metallo-proteinases of Chromobacterium lividum (NCIB 10926).

Four extracellular proteolytic enzymes (I-IV) (EC 3.4.22.-) were identified in static cultures of Chromobacterium lividum (NCIB 10926) by agar gel electrophoresis and isoelectric focusing. Proteinases I-III were freed of non-enzymic protein by chromatography on TEAE-cellulose and CM-cellulose. The enzyme mixture was then fractionated in a pH gradient by isoelectric focusing. All three enzymes were shown to be heat-labile metallo-enzymes. Optimal activity occurred at pH 5.6 for enzyme I and at pH 6.2 for enzymes II and III. Remazolbrilliant Blue-hide powder was a sensitive substrate for these enzymes. Proteinase I was also shown to degrade haemoglobin and casein effectively, but not myoglobin, ovalbumin or bovine serum albumin. Proteinases I-III exhibited molecular weight values of 75 000, 72 000 and 67 000 by exclusion chromatography and 71 000 and 66 000 by sodium dodecyl sulphate-poly-acrylamide-gel electrophoresis for enzyme I and II, respectively. The amino acid compositions of enzymes I and II were somewhat similar. Proteinase I was inhibited by EDTA, 1,2-di(2-aminoethoxy)ethane-N,N,N',N'-tetraacetic activity. Mg2+ could substitute for Ca2+ or Mn2+ for Co2+. The interrelationship of proteinases I-III is discussed.

Amino Acids↗
PubMed1975

Conformational changes in fibrous elastin due to calcium ions.

A column packed with calcium-free bovine aorta elastin provided good separations of mixtures of bile salts when water was the moving phase. Tritium-labelled cholesterol was applied to the column using dilute solutions of taurodeoxycholate in Tris-NaCl buffers as solvent. The cholesterol was quantitatively eluted as a narrow peak in a rising gradient of taurodeoxycholate. When Na+ in the buffer was replaced by Ca2+ elution of the labelled cholesterol was delayed. Control experiments in which the elastin fibres were replaced as the column packing by an inert stationary phase consisting of n-butanol immobilized by silane-treated Celite showed that the effect of the change from Na+ to Ca2+ on the solvent properties of taurodeoxycholate was small and in the opposite direction. The experiments indicated that the replacement of sodium by calcium as the ionic environment of fibrous elastin produced a configurational change towards increasing hydrophobic character.

Animals↗
PubMed1974

Salt-soluble elastin from lathyritic chicks.

The isolation of a salt-soluble homogeneous elastin from the aortas of lathyritic chicks by chromatography on DEAE-cellulose and salt precipitation is described. These new techniques, as well as some previously published by other workers, were evaluated with the help of antiserum raised in sheep against insoluble chick elastin. The purified elastin was very basic and behaved in a predictable manner in coacervation studies. The protein migrated in sodium dodecyl sulphate-polyacrylamide gels as a single band moving slightly faster than pyruvate kinase (mol.wt. 57000).

Amino Acids↗
PubMed1970

Elastogenesis.

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Aldehydes↗
PubMed1968

The isolation and characterization of a glycoprotein from human thoracic aorta.

1. A glycoprotein extracted by cold alkali from the walls of human aorta was purified by chromatography on DEAE-cellulose. 2. The compound was electrophoretically homogeneous and essentially so by chromatography on DEAE-cellulose. Ultracentrifugal examination revealed two components, and it is suggested that the faster-sedimenting component represents an aggregated form of the glycoprotein. 3. Glycoprotein preparations contained approx. 8% of carbohydrate. Digestion with Pronase yielded a glycopeptide fraction containing all the carbohydrate of the glycoprotein. The glycopeptide, of molecular weight about 7800, contained sialic acid, galactose, mannose, fucose and hexosamine in the approximate molar proportions 5:10:5:2:11. Sialic acid was terminal with respect to the polysaccharide chains. 4. Both elastase and elastomucoproteinases exhibited proteolytic activity towards the glycoprotein. Studies by other investigators have led to the conclusion that elastomucoproteinases attack protein-carbohydrate complexes occurring in intimate association with elastin in aorta and other tissues, and it is suggested that the glycoprotein may be identified with one of these compounds.

Adolescent↗