[Phosphodiesterase of cyclic nucleotides]

Abstract

Problems are considered on form multiplicity, purification and molecular weight of cyclic nucleotides phosphodiesterase. A supposition is made that the molecular weight of the catalytic subunit of the enzyme for most studied objects is about 60000. The catalytic subunit may form di- and trimers and be associated with regulatory proteins of different type. The problem of phosphodiesterase regulation is analyzed on the basis of potentialities of the equilibrium shift between the protein subunits of the enzyme; the role of cyclic nucleotides as well as of triphosphonucleotides are shown to influence the regulation of the enzymic activity. In some cases the mechanism of changes in the activity of phosphodiesterase bound with the receptor is shown to be similar to that for adenylate cyclase. In particular, the role of GTP and one of the protein subunits of phosphodiesterase in this process is stated.