The proteins released by isolated barley aleurone layers before and after gibberellic-acid treatment

✍ Scribed by J. V. Jacobsen; R. B. Knox

• Publisher: Springer-Verlag
• Year: 1974
• Tongue: English
• Weight: 917 KB
• Volume: 115
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00390516

✦ Synopsis

Isolated barley (Hordeum vulgate L.) aleurone layers released a number of proteins into an aqueous medium in the absence of gibberellic acid (GA3). Evidence from molecular weight determinations and a number of immunological tests indicated that these proteins were water-soluble endosperm proteins which apparently arose from endosperm cells which adhered to the layers during isolation. They were not aleurone-cell proteins. By means of immunofluorcscence, the water-soluble endosperm proteins were found to be concentrated around starch grains in the starchy endosperm. These proteins were resistant to hydrolysis by GA3-indueed hydrolases released from aleurone tissue, Isolated aleurone layers could be washed free of soluble endosperm proteins. After treatment with GA~, such layers released another group of proteins which were shown by immunological and electrophoretic methods to be uncontaminated by soluble endosperm proteins. The pure GA3-induced proteins were separated, using SDS-aerylamidc gel disc electrophorcsis, into 12 components which had molecular weights (monomer) from 15500 to 81000. Ten of these protein bands became radiocative if GAa-treatment of layers was carried out in the presence of radioactive amino acids, and therefore probably contained de novo synthesized proteins. The two protein bands which were not labelled contributed about 40% of the protein released by washed aleurone layers after GA 3 treatment, and their production appeared to be dependent on proteolysis.