摘要 |
The present invention relates to methods for screening for substances which are activators or inhibitors of Protein kinase B (PKB) and can be used as a kinase substrate for PKB by the use of peptides comprising a specific sequence which do not include a large hydrophobic residue at the C-terminal end. These peptides can be used in assays measuring the activity of PKB, in screening for substances which are activators or inhibitors of gene transcriptional regulation of forkhead proteins through the catalytic activities of PKB and for discrimination between the effects of compounds which mediate insulin action through transcription from those which modulate activity of enzymes involved in metabolism by phosphorylation. The substrate peptide sequence comprises the sequence 1 ArgXaaArgXaaXaaSerXaa or sequence 2, in which, Xaa in position 2 is any amino acid, preferably chosen from Pro and Gly, Xaa in positions 4 and 5 are any amino acid, preferably chosen from Thr and Ser and Xaa in position 7 is any amino acid, preferably chosen from Asn, Gln, Thr, Ser and with the proviso that the sequence does not include a large hydrophobic residue directly C-terminal to the phosphorylation site.
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