Practical physiological chemistry; a book designed for use in courses in practical physiological chemistry in schools of medicine and of science . 21).Keep these solubiUties in mind for comparison with those of edestan, to be madelater (see page 115). (3) Millons Reaction. (4) Coagiilation Test.—Place a small amount of the globuhn in a test-tube, adda little water and boil. Now add dilute hydrochloric acid and note that the pro-tein no longer dissolves. It has been coagiilated. no PHYSIOLOGICAL CHEMISTRY (5) Dissolve the remainder of the edestin in per cent hydrochloric acidand preserve th
Practical physiological chemistry; a book designed for use in courses in practical physiological chemistry in schools of medicine and of science . 21).Keep these solubiUties in mind for comparison with those of edestan, to be madelater (see page 115). (3) Millons Reaction. (4) Coagiilation Test.—Place a small amount of the globuhn in a test-tube, adda little water and boil. Now add dilute hydrochloric acid and note that the pro-tein no longer dissolves. It has been coagiilated. no PHYSIOLOGICAL CHEMISTRY (5) Dissolve the remainder of the edestin in per cent hydrochloric acidand preserve this acid solution for use in the experiments on proteans (see page 115)- Tests on Edestin Filtrate.—(i) Influence of Protein Precipitants.—^Try afew protein precipitants such as nitric acid, tannic acid, picric acid, and mercuricchloride. (2) Biuret Test. (3) Coagulation Test.—^Boil some of the filtrate in a test-tube. Whathappens? (4) Saturation with Sodium Chloride.^Saturate some of the filtrate withsolid sodium chloride. How does this result differ from that obtained uponsaturating egg albumin solution with solid sodium chloride?. Fig. 38.—ExcELSiN, The Protein of the Brazil Nut.(Drawn from crystals furnished by Dr. Thomas B; Osborne, New Haven, Conn.) (5) Precipitation by Dilution.—Dilute some of the filtrate with 10-15 volumesof water. Why does the globuhn precipitate? Glutelins It has been repeatedly shown, particularly by Osborne, that afterextracting the seeds of cereals with water, neutral salt solution, andstrong alcohol, there still remains a residue which contains proteinmaterial which may be extracted by very dilute acid or alkali. Theseproteins which are insoluble in all neutral solvents, but readily solublein very dilute acids and alkalis are called glutelins. The only memberof the group which has yet received a name is the glutenin of wheat,a protein which constitutes nearly 50 per cent of the gluten, the re-mainder being principally gliadin. It is no
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