[Mechanism of action of cAMP-dependent protein kinase. IV. Interaction of the enzyme catalytic subunit with structural analogs of histone H1].

A study was made of the specificity of the catalytic subunit of cAMP-dependent pig brain protein kinase with respect to structural analogs of the protein substrate, histone H1, namely: a) high-molecular-weight histone fragments obtained as the result of specific cleavage of histone with trypsin and N-bromsuccinimide; b) synthetic peptides-substrates; c) synthetic peptides-inhibitors. Analysis of the kinetic parameters estimated for these compounds allowed to evaluate the individual contribution of various elements of the primary and three-dimensional structure of histone in the processes of binding and phosphorylation. Factors of "near" and "remote" specificity in the protein substrate binding are suggested.