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Serotonin binding proteins (SBP) are present in the soluble fraction of bovine retina homogenates. These proteins can be precipitated with 30% ammonium sulphate and their binding and physicochemical characteristics are very similar to those of SBP in bovine and rat brain. Binding of [3H]serotonin to bovine retina SBP requires Fe2+ but not Fe3+. In the presence of an optimal concentration of Fe2+ (0.1 mM), these proteins behave as a single class of non-cooperative sites for [3H]serotonin (Bmax = 242 +/- 10 pmol/mg protein, KD = 0.22 +/- 0.44 microM). Competition binding studies reveal that serotonin analogs possessing an hydroxyl group on the indole ring and catecholamine analogs possessing an intact catechol moiety are potent competitors (K1 from 0.12 to 0.3 microM). In both cases, the affinity is strongly decreased if aromatic hydroxyl groups are methoxylated. Catecholamine SBP interactions can also be demonstrated directly by binding experiments with [3H]dopamine. Binding of this catecholamine is greatly enhanced by Fe2+, to a lesser extent by Cu2+ and Mn2+, but not by Fe3+. The Fe(2+)-dependent binding component is saturable (Bmax = 505 +/- 30 pmol/mg protein. KD = 0.34 +/- 0.04 microM). The SBP from bovine retina show the same physicochemical properties as SBP from bovine and rat brain: they elute immediately after the void volume on a Sephacryl S100 HR (1.6 x 140 cm) gel filtration column (reflecting aggregation) and they migrate with apparent molecular weights of respectively 43 kDa and 57 kDa on native polyacrylamide gel electrophoresis. The serotonin-storing role of SBP in serotonergic neurones has already been well documented.(ABSTRACT TRUNCATED AT 250 WORDS)
M Jimenez Del Rio, and
J Pinxteren, and
W De Potter, and
G Ebinger, and
G Vauquelin
October 1981,
Experimental eye research,
M Jimenez Del Rio, and
J Pinxteren, and
W De Potter, and
G Ebinger, and
G Vauquelin
February 1981,
Annals of the New York Academy of Sciences,
M Jimenez Del Rio, and
J Pinxteren, and
W De Potter, and
G Ebinger, and
G Vauquelin
May 1976,
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M Jimenez Del Rio, and
J Pinxteren, and
W De Potter, and
G Ebinger, and
G Vauquelin
October 1976,
Biochimica et biophysica acta,
M Jimenez Del Rio, and
J Pinxteren, and
W De Potter, and
G Ebinger, and
G Vauquelin
January 1980,
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M Jimenez Del Rio, and
J Pinxteren, and
W De Potter, and
G Ebinger, and
G Vauquelin
January 1984,
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M Jimenez Del Rio, and
J Pinxteren, and
W De Potter, and
G Ebinger, and
G Vauquelin
September 1978,
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M Jimenez Del Rio, and
J Pinxteren, and
W De Potter, and
G Ebinger, and
G Vauquelin
July 1981,
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M Jimenez Del Rio, and
J Pinxteren, and
W De Potter, and
G Ebinger, and
G Vauquelin
June 1995,
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M Jimenez Del Rio, and
J Pinxteren, and
W De Potter, and
G Ebinger, and
G Vauquelin
August 1982,
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