Enzymatic phosphorylation of food proteins by purified and recombinant protein kinase CK2

• Published in: Die Nahrung 1998-08, Vol.42 (3-4), p.145-147
• Main Authors: Chardot, T., Benetti, P.H., Canonge, M., Kim, S.-I., Chaillot, D., Fouques, D., Meunier, J.-C.
• Format: Article
• Language: English
• Subjects: Animal, plant, fungal and microbial proteins, edible seaweeds and food yeasts; Biological and medical sciences; Biotechnology; Calcium - metabolism; Casein Kinase II; Catalysis; Chemical and Process Engineering; Cloning, Molecular; Dietary Proteins - metabolism; Engineering Sciences; Enzyme engineering; Food engineering; Food industries; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Life Sciences; Methods. Procedures. Technologies; Milk Proteins - metabolism; Miscellaneous; Phosphorylation; Plant Proteins - metabolism; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - isolation & purification; Protein-Serine-Threonine Kinases - metabolism; Recombinant Proteins - genetics; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Solubility; Yeasts - metabolism
• ISSN: 0027-769X; 1521-3803; 1611-6070
• DOI: 10.1002/(SICI)1521-3803(199808)42:03/04<145::AID-FOOD145>3.0.CO;2-2

Protein kinase CK2 formerly called casein kinase II is a protein kinase able to phosphorylate more than 100 proteic substrates. We have purified protein kinase CK2 from the yeast Y. lipolytica to phosphorylate milk and plant reserve proteins to a significant extent. In the case of plant reserve proteins, which are polymeric substrates, not all subunits are substrate for protein kinase CK2, even if non phosphorylated subunits contain significant potent phosphorylations sites. Best substrates were soy β‐conglycinin (0.72 P/mol) and dephosphorylated caseins (0.5 P/mol). We have studied some functional properties of phosphorylated caseins. Solubility was improved for all pH values but pI. Sensitivity to calcium has also been assessed, and it is sligtly improved upon phosphorylation. We have cloned the catalytic subunit of protein kinase CK2 from yeast Y. lipolytica. The recombinant catalytic subunit expressed in E. coli was active and displayed kinetic properties similar to those of the purified enzyme. The recombinant catalytic subunit was able to phosphorylate plant reserve proteins and milk proteins to a significant extent. Best substrates were soy β‐conglycinin (1.0 P/mol), and glycinin (0.59 P/mol).