A STUDY ON THE GLUCOSAMINE-CONTAINING CONSTITUENTS OF THE SEEDS OF KIDNEY BEANS (PHASEOLUS VULGARIS)

STUDIES ON THE EXTRACTION OF NITROGENOUS AND PHOSPHORUS-CONTAINING MATERIALS FROM THE SEEDS OF KIDNEY BEANS (PHASEOLUS VULGARIS)

1. The conditions of extracting nitrogenous, phosphorus-containing and glucosamine-containing components of the seeds of kidney bean have been studied. 2. The dispersing of proteins was incomplete below pH 7, and the exact amount of protein extracted depended on the pH and the ionic strength of the solvent. 3. The extraction of proteins was practically complete in the range pH 7-9, but the relative amounts of the individual proteins obtained still depended on the pH of the extracting media, indicating a pH-dependent association-dissociation reaction between the protein molecules present. 4. The extraction of phosphorus-containing material showed an optimum at pH 6-7, and only a part of this was removed on dialysis. The precipitates obtained with trichloroacetic acid, on the other hand, retained very little phosphorus-containing material. 5. The significance of these findings is discussed.

Glycoprotein Metabolism in the Cotyledons of Pisum sativum during Development and Germination

The glycoprotein nature of legumin and vicilin, the reserve globulins in the cotyledons of Pisum sativum was studied. Legumin from mature seed was found to contain 1% neutral sugars (mannose and glucose) and 0.1% amino sugar (glucosamine), whereas vicilin contained 0.3% neutral sugar (mannose) and 0.2% amino sugar (glucosamine). On the basis of the incorporation of (14)C-labeled glucosamine, it appeared that not all of the component subunits of the reserve proteins are glycosylated to the same extent. In addition, it has been established that glycosylation occurs after peptide synthesis. During seed development there was a change in neutral sugars and amino sugar ratio in vicilin. During germination, the neutral sugars and the amino sugar content of the glycoproteins declined. These findings are discussed in relation to the synthesis and degradation of the glycosyl component of the glycoproteins.

The isolation of two proteins, glycoprotein I and a trypsin inhibitor, from the seeds of kidney bean (Phaseolus vulgaris)

1. The isolation of two proteins from the seeds of kidney bean is described. 2. The individual steps in the purification procedure included: extraction of the seeds at pH9.0, dialysis, first against pH9.0 and then against pH5.0 buffers, high-voltage electrophoresis of the proteins soluble at pH5.0 and chromatography on Sephadex G-200, Sephadex G-75 and DEAE-Sephadex columns. 3. Of the two proteins isolated, the first and larger component was a glycoprotein and its carbohydrate part was mainly composed of d-mannose and d-glucosamine together with smaller amounts of arabinose, xylose and fucose. 4. The second protein component isolated was a trypsin inhibitor and was almost entirely devoid of sugars but contained a firmly bound pinkish-blue pigment. 5. The amino acid composition of the two proteins was determined. 6. The glycoprotein contained very little if any cyst(e)ine but was relatively rich in aromatic amino acids, whereas the trypsin inhibitor had an unusually high cystine content (nearly 15%) but was relatively poor in valine and in aromatic amino acids.