Enzymatic phosphorylation of soy globulins by the protein kinase CK2. Determination of the phosphorylation sites of beta-conglycinin alpha subunit by mass spectrometry.
Beta-conglycinin alpha subunit has been phosphorylated using a cAMP-independent protein kinase (CK2) purified from the yeast Yarrowia lipolytica. CK2 is known to phosphorylate serines and threonines in the consensus sequence Ser/Thr-X-X-Asp/Glu. Only 0.5 to 1 mol P/mol alpha subunit was incorporated although seven consensus sequences are present. Phosphorylated beta-conglycinin alpha subunit (P-alpha) was digested by trypsin. The resulting peptides were analysed by RP-HPLC coupled to electrospray ionisation mass spectrometry (LC-ESMS). Two phosphopeptides were identified corresponding to 70-89 and 116-127 sequences with Ser 75 and Ser 117 phosphorylated respectively. Ser 75 is one of the predicted phosphorylation sites according to the consensus sequence criteria. Ser 117 is inside a very acidic peptide but does not belong to a previously described consensus sequence.
Fouques
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D
Institut National de la Recherche Agronomique, Laboratoire de Chimie Biologique, Thiverval-Grignon, France.
Ralet
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MC
Mollé
D
D
Léonil
J
J
Meunier
J C
JC
D052179:Antigens, Plant; D047390:Casein Kinase II; D002851:Chromatography, High Pressure Liquid; D005916:Globulins / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D013058:Mass Spectrometry; D010455:Peptides / Q000737:chemistry; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D055314:Seed Storage Proteins; D030262:Soybean Proteins / Q000378:metabolism*; D013025:Glycine max / Q000378:metabolism*; D014357:Trypsin / Q000737:chemistry; D015003:Yeasts / Q000201:enzymology / Q000235:genetics / Q000378:metabolism
D052179:Antigens, Plant; D005916:Globulins; D010455:Peptides; D011994:Recombinant Proteins; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D014357:Trypsin