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

1. The constituents of the seeds of kidney beans containing glucosamine that could be released by acid hydrolysis (0.5 n-hydrochloric acid at 100 degrees ) were extracted into the phenol-rich phase on partitioning between phenol and water at 70 degrees . 2. These materials were also brought into solution on extracting the seeds with water (incomplete), or preferably with a slightly alkaline buffer in the absence of phenol. When these solutions were heated at 100 degrees or treated with trichloroacetic acid, all the materials containing acid labile glucosamine were carried down with the precipitate. Treatment with pepsin rendered the materials containing glucosamine soluble again. 3. All proteins in these extracts of kidney bean were found to be associated with various amounts of neutral and amino sugars by high-voltage electrophoresis and chromatography on Sephadex G-200 columns. 4. The isolation and crystallization of the main sugar components, d-glucosamine and d-mannose, are described and their significance in plant glycoproteins is discussed.

AN ELECTROPHORETIC INVESTIGATION OF GROUNDNUT PROTEINS: THE STRUCTURE OF ARACHINS A AND B

1. The proteins of the groundnut cotyledon have been fractionated and analysed by DEAE-Sephadex chromatography and acrylamide-gel electrophoresis. Seventeen components were detected. 2. A new method is described for the preparation of arachin, using calcium precipitation. The product contains at least 99% of arachin. 3. The theory of acrylamide-gel electrophoresis is developed and applied to the arachin system to predict the molecular weight of one sub-unit of arachin. 4. A variant form of arachin, arachin B, has been discovered. Of 81 nuts, 27 contained only arachin B, 53 contained both arachin A and B, and one contained arachin A only. This is almost certainly a polymorphism of arachin; this is the first example of polymorphism to be reported in plant proteins. 5. A combination of controlled denaturation, electrophoretic analysis, ultracentrifuge and Sephadex filtration data has shown that arachin A contains four different kinds of peptide chains (alpha, beta, gamma and delta). Arachin B contains only beta, gamma and delta chains. 6. The most probable structure for arachin B, mol.wt. 330000 form, is 8 beta, 2 gamma and 2 delta chains, and for arachin A, 4 alpha, 4 beta, 2 gamma and 2 delta chains. Arachin without beta chains was not found. 7. The alpha and beta chains have mol.wts. of about 35000 and the gamma and delta chains of about 10000. 8. Three N-terminal groups were found: the alpha and beta chains both terminate in glycine; the gamma and delta chains terminate in isoleucine and glutamic acid. 9. Arachin contains no carbohydrate. 10. Disulphide bonds are not important in arachin: there are none between the alpha, beta, gamma and delta chains. 11. The amino acid compositions of arachins A and B are very similar. Glutamic acid and aspartic acid residues are exceptionally frequent.

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.

STUDIES ON A VEGETABLE PROTEIN MIXTURE BASED ON PEANUT AND SOYA FLOURS

A vegetable protein mixture made up of 50% edible peanut flour and 50% full‐fat soya flour and fortified with 1% each of 1‐lysine and dlmethionine and adequate amts of essential vitamins and minerals has been developed. Two formulations, 1) unseasoned and 2) seasoned have been developed for use in sweet and savoury preparations; both the formulations keep well for more than 9 months at 37C when stored in hermetically sealed cans. The protein mixture contains 49.2% protein which possesses a PER of 2.80 and NPU of 72.3; these values compare favourably with those for skim milk powder. Growth studies on albino rats and feeding trials on school children have shown that the protein mixture has a significant supplementary value to poor cereal‐based diets. The mixture fortified with methionine alone is equally effective as skim milk powder for the treatment of kwashiorkor.