Patent ID: 8802926

Claim:
An isolated polynucleotide encoding a mutant large subunit of a maize, barley, wheat, or rice plant ADP-glucose pyrophosphorylase protein, or a biologically-active fragment or variant of said mutant protein, wherein said mutant protein encoded by said polynucleotide comprises an amino acid mutation at the amino acid corresponding to the histidine at position 333 in the amino acid sequence of a wild type large subunit of ADP-glucose pyrophosphorylase protein of maize, wherein said amino acid corresponding to the histidine at position 333 is substituted with an amino acid that confers heat stability to said protein, and wherein when said mutant large subunit protein is expressed to form a mutant ADP-glucose pyrophosphorylase enzyme, said mutant enzyme, or a biologically-active fragment of said mutant enzyme, exhibits increased heat stability relative to wild type ADP-glucose pyrophosphorylase enzyme.