Immunologic characterization of the photoreceptor outer segment cyclic GMP phosphodiesterase

R. L. Hurwitz, A. H. Bunt-Milam, J. A. Beavo

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32 Scopus citations


High affinity (K(D) ~ 1 x 10-9 M) monoclonal antibodies (ROS-1 and ROS-2) were prepared to bovine photoreceptor outer segment cGMP phosphodiesterase. ROS-1 immunoadsorbed >95% of the cGMP phosphodiesterase activity from a detergent-solubilized bovine retine extract while ROS-2 immunoadsorbed only a subfraction of the same activity. Sodium dodecyl sulfate gel analysis of these immunoadsorbates demonstrated that ROS-1 and ROS-2 specifically adsorbed only peptides that comigrated with purified rod outer segment phosphodiesterase. Limited trypsin digestion of purified rod outer segment phosphodiesterase greatly reduced its affinity for ROS-1 but not ROS-2. When a crude heat-stable inhibitor fraction was added back to the activated enzyme, the affinity for ROS-1 was restored, suggesting that the inhibitor was necessary for ROS-1 binding. ROS-1 but not ROS-2 was found to inhibit cGMP phosphodiesterase which had been activated either by dilution or guanyl nucleotide. The inhibitory property of ROS-1 may provide a useful probe for directly studying the effects of this phosphodiesterase on the phototransduction response in the retina. Sodium dodecyl sulfate gel analysis demonstrated that the ROS-1 immunoadsorbates from mammals, fish, and amphibia contained peptides of similar mobility. Immunocytochemistry performed with ROS-1 and fluorescein isothiocyanate-conjugated rabbit anti-mouse IgG localized the antigenic determinant to both rod and cone outer segments suggesting the presence of an antigenically similar phosphodiesterase in both types of photoreceptors.

Original languageEnglish (US)
Pages (from-to)8612-8618
Number of pages7
JournalJournal of Biological Chemistry
Issue number13
StatePublished - 1984

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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