Purification and principal properties of the casein kinase ii purified from the yeast Yarrowia lipolytica

Abstract

• 1.

  1. A protein kinase from the lipolytic yeast Yarrowia lipolytica has been purified to nearby homogeneity.

• 2.

  2. The enzyme is able to phosphorylate casein and soybean purified storage proteins (β-conglycinin and glycinin) in the absence of cAMP.

• 3.

  3. Its activity and autophosphorylation are inhibited by very low concentrations of heparin.

• 4.

  4. Its native structure which is a tetramer of 170 kDa composed of two kinds of subunits, α and β (42 and 35 kDa, respectively), β being autophosphorylated. Through ordered aggregation phenomena 1800 and 580 kDa species can also be observed.

• 5.

  5. This enzyme belongs to the casein kinase II family.

• 6.

  6. We describe the use of a protein kinase to phosphorylate easily available reserve proteins. This system is a promising tool to study the specificity of the enzyme, and to find out the link between the phosphorylation, conformational changes, and functional properties.