Cyclic nucleotide-dependent protein kinase in the thyroid: partial purification and characterization.

Abstract

Cyclic nucleotide dependent protein kinase (CNDPK) has been previously demonstrated in thyroid tissue. We confirm its presence in bovine and rat thyroid tissue, and describe a procedure for the partial purification of bovine CNDPK. This involves an acid precipitation step, followed successively by Sephadex G-200 filtration, DEAE-cellulose and hydroxylapatite chromatography. A 70–100-fold increase in specific activity was achieved. Evaluation of bovine thyroid CNDPK showed half maximal phasphorylation of calf thymus histone type IIA at a concentration of 100 μg histone per standard assay in the presence and absence of cyclic-AMP. The Km for ATP was 3.3 × 10-5M in the presence and absence of cyclic-AMP. The Km for cyclic-AMP was 4 × 10-8M, and that for cyclic- IMP 6 × 10-7M. Cyclic-AMP and cyclic-IMP were equally the most stimulatory of the cyclic nucleotides (343 and 334% of control respectively), followed by cyclic-GMP (171%), cyclic- CMP and cyclic UMP (144%), and dibutyryl cyclic-AMP (125%). Cyclic-TMP ...