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Biomedical subjects

K D Hapner

Publications and source records attributed to K D Hapner.

9 recordsLinked to original sources
PubMed1979

Isolation and properties of a lectin from sainfoin (Onobrychis viciifolia, Scop.).

A glycoprotein capable of binding simple carbohydrates and causing hemagglutination has been isolated from seeds of the legume plant sainfoin (Onobrychis viciifolia, Scop. var Eski). The phytolectin was prepared by affinity chromatography of pH 7.0 sodium phosphate extracts on columns of Sepharose-4B containing covalently attached D-mannose. Molecular weight determinations showed the lectin to be a dimer consisting of 26 000 dalton, non-covalently associated monomers. Amino acid analyses indicated high amounts of aspartate, glutamate, threonine and serine which accounted for 41% of all amino acids. One residue of cysteine was present and methionine was totally absent. The lectin contained 2.6% (w/w) neutral carbohydrate and two residues of N-acetylglucosamine/monomer. Carbohydrate-binding specificity was directed toward D-mannose and D-glucose and their alpha-glycosidic derivatives. The purified protein agglutinated cat erythrocytes at 5 micrograms/ml. Antiserum to seed lectin showed a single common immunoprecipitation line in Ouchterlony double diffusion against both the seed and root antigen. Lectin isolated from sainfoin seedling roots showed molecular weight, amino acid and carbohydrate values similar to that of the seed lectin.

Amino Acids↗
PubMed1979

The glycosyl moiety of lectin from sainfoin (Onobrychis viciifolia, Scop.).

A lectin isolated from the seeds of sainfoin (Onobrychis viciifolia, Scop. var Eski) has been shown to be a glycoprotein containing 2.6% (w/w) neutral carbohydrate and 1.6% (w/w) glucosamine (Hapner, K.D. and Robbins, J.E. (1979) Biochim. Biophys. Acta 580, 186--197) A homogeneous glycopeptide accounting for 70% of the original glycoprotein carbohydrate was isolated from pronase digests of the lectin by gel filtration chromatography. Gas-liquid chromatographic and amino acid analyses showed the glycosyl portion to contain glucosamine, mannose, xylose and fucose in molar ratio to glycopeptide of 1.8 : 1.8 : 0.7 : 0.9. The amino acid sequence was determined as H2N-Ser-Asn(glycosyl)-glu-Thr-COOH. The glycosyl moiety was attached to the peptide through N-glycosidic linkage between asparagine and glucosamine.

Amino Acids↗
PubMed1978

Some phytotoxic glycopeptides from Ceratocystis ulmi, the Dutch Elm Disease pathogen.

Ceratocystis ulmi, the causal agent of Dutch Elm Disease, produces phytotoxic glycopeptides in culture. A mixture of phytotoxic glycopeptides has been prepared by affinity chromatography on a concanavalin A-Sepharose column and collectively they have been termed the toxin. The polydisperse component that makes up the majority of toxin (80%) by weight has a molecular weight of about 2.7.10(5). The large molecular weight component (less than 5%) elutes at the void volume of a Bio-Gel A 50 m column. The other component (15%) appears as a trailing peak on the edge of the major component and has an approximate molecular weight of 7.10(4). The toxin is composed of 83% sugar residues, primarily rhamnose and mannose, and 7% amino acid residues. Methylation analysis coupled with mild acid hydrolysis indicates that the backbone of the polysaccharide portion of the toxin is composed of alpha -1,6-linked mannosyl residues with a 3-linked terminal rhamnosyl residue linked to C-3 of almost every mannosyl residue. The carbohydrate portion of the molecule is linked to the peptide via O-glycosidic linkages to both threonyl and seryl residues. All three components of the toxin are capable of causing wilt in stem cuttings of American elm.

Amino Acids↗
PubMed1978

Rhodamine immunohistofluorescence applied to plant tissue.

Tissue slices from the roots and seeds of sanifoin (Onobrychis viciifolia, Scop.) exhibit bright autofluorescence when illuminated with blue (495 nm) light. This autofluorescence is indistinguishable from the fluorescence emission of fluorescein, the commonly used fluorochrome in immunohistochemical staining procedures. Rhodamine isothiocyanate, when coupled to immunoglobulin, and excited with green light at 546 nm, exhibits a reddish-orange fluorescence with an emission maximum at 590 nm. Plant tissue has little or no autofluorescence when illuminated at this wavelength and viewed with a 580 nm barrier filter. Therefore, use of rhodamine for immunohistochemical localization in plant tissue avoids interpretative complications due to inherent autofluorescence.

Antigens↗
PubMed1975

The structural subunit of glucose-6-phosphate dehydrogenase (baker's yeast).

The subunit molecular weight of glucose-6-phosphate dehydrogenase (G6PD) from baker's yeast has been evaluated. The subunit molecular weight value is shown to be 25,500 daltons by analytical ultracentrifugation, SDS-polyacrylamide gel electrophoresis, and the number of peptides produced by CNBr cleavage. The number of NADP binding sites was determined to be one per 25,500 dalton unit.

Amino Acids↗