Cereal Chem 56:110 - 117.  |  VIEW ARTICLE
Protein Metabolism in Developing Endosperms of High-Lysine and Normal Barley.

P. R. Shewry, H. M. Pratt, M. M. Leggatt, and B. J. Miflin. Copyright 1979 by the American Association of Cereal Chemists, Inc. 

In barley cv. Bomi synthesis of hordein occurred between two and five weeks after anthesis, and this fraction accounted for approximately 50% of the total nitrogen of the mature endosperm. In the high-lysine mutant Ris phi 1508, however, hordein accounted for only 15% of the mature endosperm N and synthesis was essentially complete at four weeks. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing of the hordein fractions demonstrated only minor changes in the relative polypeptide compositions of both varieties during endosperm development. In Ris phi 1508 the amounts of nonprotein nitrogen (NPN) and salt-soluble proteins increased until three and four weeks, respectively, whereas in Bomi the amount of NPN fell and salt-soluble protein increased between two and three weeks, after which the amounts of both fractions remained constant. In Ris phi 1508 these fractions accounted for about 18 and 25% of the mature endosperm N compared with 9 and 12% in Bomi. The amount of glutelin N per endosperm was similar in both lines and represented about 20% of the notal N in Bomi and 29% in Ris phi 1508. Incorporation of radioactivity from 14CO2 into the N fractions of the developing endosperms was consistent with the changes in total amounts. Ris phi 1508 showed an increased incorporation of 14CO2 in lipids, and further investigation of this fraction showed that the mutant had increased total amounts of both neutral and polar lipids. It was concluded that the Ris phi 1508 mutation acts throughout endosperm development and affects the synthesis of the major components of the seed---proteins, lipids, and carbohydrates.