A LOW-K(M), ROLIPRAM-SENSITIVE, CAMP-SPECIFIC PHOSPHODIESTERASE FROM HUMAN BRAIN - CLONING AND EXPRESSION OF CDNA, BIOCHEMICAL-CHARACTERIZATION OF RECOMBINANT PROTEIN, AND TISSUE DISTRIBUTION OF MESSENGER-RNA

作者：MCLAUGHLIN MM; CIESLINSKI LB; BURMAN M; TORPHY TJ; LIVI GP

来源：Journal of Biological Chemistry, 1993, 268(9): 6470-6476.

We have isolated cDNA clones from human frontal cortex cDNA libraries that encode a unique subtype of the low-K(m), cAMP-specific phosphodiesterases (PDEs IV). The 564-amino acid sequence of the protein (human brain PDE IV (hPDE IV(B)) shows significant homology to a PDE IV subtype expressed in human monocytes (hPDE IV(A)), particularly within the approximately 300-amino acid PDE IV catalytic domain. The degree of protein sequence identity is much greater between hPDE IV(B) and a homolog derived from rat brain (92% over 562 amino acids) than between hPDE IV(B) and hPDE IV(A) (76% over 538 amino acids), suggesting a greater subtype-specific versus species-specific conservation of protein sequence. Analysis of the distribution of hPDE IV(B) mRNA expression revealed a restricted pattern, with an approximately 4-kilobase mRNA detected in brain, heart, lung, and skeletal muscle and not in placenta, liver, kidney, or pancreas. An additional approximately 5-kilobase hPDE IV(B)-related mRNA species was detected in brain tissue. Recombinant hPDE IV(B) displayed all of the expected kinetic characteristics for a PDE IV, including sensitivity to the isozyme-selective inhibitor rolipram (K(i) = 0.085 muM). Scatchard analysis of (R)-[H-3]rolipram binding data suggested the presence of two noninteracting high affinity rolipram-binding sites (K(d) = 0.4 and 6 nM) or a negatively cooperative interaction among multiple binding sites.

• 出版日期1993-3-25