In Vitro Synthesis and Processing of Wheat alpha-Amylase : TRANSLATION OF GIBBERELLIC ACID-INDUCED WHEAT ALEURONE LAYER RNA BY WHEAT GERM AND XENOPUS LAEVIS OOCYTE SYSTEMS

Wheat (Triticum aestivum) RNA was used to program synthesis of the α-amylase protein by Xenopus laevis oocytes. A 41,500-dalton protein was made which was identified as α-amylase by immunoprecipitation with rabbit anti-α-amylase antiserum raised against the purified wheat protein and by its co-migration with authentic α-amylase on sodium dodecyl sulfate polyacrylamide gels. Synthesis of α-amylase was dependent upon injection of RNA extracted from gibberellic acid-induced aleurone layers from wheat. The amount of α-amylase produced was proportional to the amount of RNA injected and reached a plateau within 4 hours after injection. When the same RNA was translated in a wheat germ cell-free translation system, a 43,000-dalton protein was produced. Addition of dog pancreas microsomal membranes to the wheat germ translation system resulted in processing of the α-amylase protein to a form which co-migrated with authentic α-amylase purified from malted wheat and with the protein synthesized in oocytes.