Cloning and Characterization of PDE7B, a cAMP-Specific Phosphodiesterase

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 97; no. 1; pp. 472 - 476
• Main Authors: Hetman, J. M., Soderling, S. H., Glavas, N. A., Beavo, J. A.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 04.01.2000; National Acad Sciences; National Academy of Sciences; The National Academy of Sciences
• Subjects: 3',5'-Cyclic-AMP Phosphodiesterases - chemistry; 3',5'-Cyclic-AMP Phosphodiesterases - genetics; 3-isobutyl-1-methylxanthine; Amino Acid Sequence; Amino acids; Animals; Baculoviridae; Base Sequence; Binding Sites; Biological Sciences; Cloning; Cloning, Molecular; Complementary DNA; Cyclic Nucleotide Phosphodiesterases, Type 7; Databases as Topic; dipyridamole; Enzyme Inhibitors - pharmacology; Enzymes; Expressed Sequence Tags; Inhibitory concentration 50; Isoenzymes - chemistry; Isoenzymes - genetics; Kinetics; Messenger RNA; Molecular Sequence Data; Open reading frames; Pancreas; papaverine; Pharmacology; Recombinant Proteins; RNA, Messenger - metabolism; Sequence Alignment; Skeletal muscle; Substrate Specificity; T lymphocytes
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.97.1.472

A member of the phosphodiesterase (PDE)7 family with high affinity and specificity for cAMP has been identified. Based on sequence homologies, we designate this PDE as PDE7B. The full-length cDNA of PDE7B is 2399 bp, and its ORF sequence predicts a protein of 446 amino acids with a molecular mass of 50.1 kDa. Comparison of the predicted protein sequences of PDE7A and PDE7B reveals an identity of 70% in the catalytic domain. Northern blotting indicates that the mRNA of PDE7B is 5.6 kb. It is most highly expressed in pancreas followed by brain, heart, thyroid, skeletal muscle, eye, ovary, submaxillary gland, epididymus, and liver. Recombinant PDE7B protein expressed in a Baculovirus expression system is specific for cAMP with a Kmof 0.03 μ M. Within a series of common PDE inhibitors, it is most potently inhibited by 3-isobutyl-1-methylxanthine with an IC50of 2.1 μ M. It is also inhibited by papaverine, dipyridamole, and SCH51866 at higher doses. PDE7A and PDE7B exhibit the same general pattern of inhibitor specificity among the several drugs tested. However, differences in IC50for some of the drugs suggest that isozyme selective inhibitors can be developed.