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The norpAH44 phototransduction mutant of Drosophila melanogaster, an allele that, on eclosion, does not exhibit a receptor potential was found, at later ages, to undergo light and temperature dependent degeneration of its photoreceptors as well as decreases in rhodopsin concentration. Pseudopupil measurements and light and electron microscopy were used to(More)
Five GTP binding proteins in rat cerebral cortex synaptic membranes were identified by photoaffinity labelling with [3H] or [32P](P3-azido-anilido)-P1-5' GTP (AAGTP). When AAGTP-treated membranes were incubated with colchicine or vinblastine and subsequently washed, a single AAGTP-labelled protein of 42 kD was released into the supernatant. About 30% of the(More)
Particularly stable elements of noncovalent structure in bovine carbonic anhydrase have been detected and studied. These are present in a highly populated intermediate state formed during denaturation of the enzyme with guanidinium chloride. The intermediate has been detected by analysis of the denaturation profiles, and some of its structural properties(More)
Mosquito rhodopsin is a digitonin-soluble membrane protein of molecular weight 39,000 daltons, as determined by sodium dodecyl sulfate gel electrophoresis. The rhodopsin undergoes a spectral transition from R515-520 to M480 after orange illumination. The visual pigment apoprotein, opsin, is the major membrane protein in the eye. Protein synthesis in the(More)
In this report, we show that fluoride activates dark-adapted rod outer segment phosphodiesterase, and that this activation is mediated, in analogy with adenylate cyclase, through a GTP binding protein. The GTP binding protein is released from dark-adapted rod outer segment membranes by exposure to fluoride and subsequent centrifugation. The 39-kilodalton(More)
Previous studies have noted profound similarities between the regulation of light-activated 3',5'-cyclic nucleotide phosphodiesterase (3',5'-cyclic-nucleotide 5'-nucleotidohydrolase, EC 3.1.4.17) in retinal rods and hormone-activated adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] in a variety of tissues. We report here the functional(More)
The amphibian photoreceptor rod outer segment contains a guanine nucleotide-binding complex which consists of a 39,000-dalton polypeptide that binds guanine nucleotides (G protein), a 36,000-dalton polypeptide (H protein), and an approximately 6,500-dalton polypeptide. Sensitivity to trypsin proteolysis was utilized as a probe of structure-function(More)
PURPOSE To determine whether a new cyclic GMP analog, 2'-O-(4-benzoyl)benzoylguanosine 3',5' cyclic monophosphate (BB-cGMP), significantly reduces intraocular pressure in either normotensive or hypertensive eyes of rabbits. METHODS Intraocular pressure of normal adult rabbits and/or rabbits with alpha-chymotrypsin-induced ocular hypertension was measured(More)
Light-induced activation of cyclic GMP phosphodiesterase (PDE) in the outer segments of vertebrate rod photoreceptors has been suggested as a step in the transduction process linking the absorption of light by rhodopsin with a hyperpolarization of the plasma membrane. Activation of PDE is mediated by a 'GTP-binding protein' (G). As a result of interaction(More)