Plasma amino-acids in hereditary retinal disease. Ornithine, lysine, and taurine.

Berson, Eliot L.; Schmidt, Susan Y.; Rabin, Arnold R.

doi:10.1136/bjo.60.2.142

Cited by 59 publications

(17 citation statements)

References 11 publications

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“…However, the high taurine concentrations in brain suggest an important role for transport systems alongside the biosynthesis of taurine. Indeed a decreased Km and Vmax of taurine uptake was implicated in retinitis pigmentosa (13,14).…”

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confidence: 99%

Cloning and expression of a cDNA encoding the transporter of taurine and beta-alanine in mouse brain.

Liu

López-Corcuera²,

Nelson³

et al. 1992

Proc. Natl. Acad. Sci. U.S.A.

256

161

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A taurine/fl-alanine transporter was cloned from a mouse brain cDNA library by screening with a partial cDNA probe of the glycine transporter at low stringency. The deduced amino acid sequence predicts 590 amino acids with typical characteristics of the sodium-dependent neurotransmitter transporters such as sequence homology and membrane topography. However, the calculated isoelectric point of the taurine/fi-alanine transporter is more acidic (pI = 5.98) than those (pI > 8.0) of other cloned neurotransmitter transporters. Xenopus oocytes Injected with cRNA of the cloned transporter expressed uptake activities with K. = 4.5 FM for taurine and K. = 56 FM for (3-alanine. Northern hybridization showed a single transcript of 7.5 kil9bases that was highly enriched in kidney and distributed evenly in various parts of the brain. In situ hybridization showed the mRNA of the taurine/(3-alanine transporter to be localized in the corpus callosum, striatum, and anterior commisure. Specific localization ofthe taurine/palanine transporter in mouse brain suggests a-potential function for taurine and (3-alanine as neurotransmitters.

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mentioning

confidence: 99%

Cloning and expression of a cDNA encoding the transporter of taurine and beta-alanine in mouse brain.

Liu

López-Corcuera²,

Nelson³

et al. 1992

Proc. Natl. Acad. Sci. U.S.A.

256

161

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“…Subsequently, a total of 30 patients with hyperomithinemia and GA have been reported (4)(5)(6) and the inheritance of this disorder has been shown to be autosomal recessive (4).…”

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confidence: 99%

Gyrate atrophy of the choroid and retina: deficiency of ornithine aminotransferase in transformed lymphocytes.

Valle¹,

Kaiser-Kupfer²,

Valle³

1977

Proc. Natl. Acad. Sci. U.S.A.

118

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Gyrate atrophy of the choroid and retina is an inherited form of chorioretinal degeneration associated with hyperornithinemia. We measured the activity of ornithine aminotransferase (L-ornitline2-oxo-acid Subsequently, a total of 30 patients with hyperomithinemia and GA have been reported (4-6) and the inheritance of this disorder has been shown to be autosomal recessive (4).Takki (2, 3) and others (7) have suggested that a deficiency of ornithine aminotransferase (OAT; L-ornithine:2-oxo-acid aminotransferase, EC 2.6.1.13) is responsible for GA. This mitochondrial matrix enzyme catalyzes the pyridoxal phosphate-dependent transamination of ornithine to glutamic -ysemialdehyde which is in spontaneous, nonenzymatic equilibrium with Al-pyrroline-5-carboxylic acid (8) (PC) (Fig. 1). No measurements of OAT activity in tissues or cells of GA patients have been published, however.t Previous studies (9) have shown that barely measurable levels of OAT activity are present in resting lymphocytes, but in association with phytohemagglutinin-stimulated transformation there is a 15-fold increase in the specific activity of lymphocyte OAT to levels that can be measured easily and reliably. Utilizing this response to transformation, we measured the activity of OAT in lymphocytes of a GA patient, her daughter, and normal individuals. We found a marked deficiency of OAT in transformed lymphocytes of the patient and intermediate values in those of the obligate heterozygote.The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact. 5159CASE REPORT Our patient, a 34-year-old Brazilian woman of Portuguese descent, noted the onset of difficulty in night vision during the second decade and had had-bilateral posterior subcapsular cataracts removed at age 25 years. Ophthalmoscopic examination revealed sharply demarcated, whitish, confluent areas of chorioretinal atrophy in the midperiphery of the fundus extending toward the posterior pole. The atrophic areas had scalloped margins and were accompanied by a fine pigmentation of the macula. Her parents were unrelated; one of three siblings had progressive loss of vision beginning early in his third decade.The patient's daughter was 3 years old and had no physical or ophthalmological abnormalities. METHODSLymphocyte Culture. Peripheral blood lymphocytes were prepared from fresh, heparinized whole blood obtained from our patient, her daughter, and two male and one female healthy normal subjects whose ages ranged from 22 to 33 years. Lymphocytes were separated from other blood cells by centrifugation on Ficoll-Hypaque gradients and then washed three times in balanced salt solution (9).Washed lymphocytes were cultured at a density of 5 X 105 cells per ml in RPMI-1640 medium supplemented with 10% fresh plasma, 4 mM glutamine, penicillin (50 units/ml), and streptomycin (50 ,ug/ml). Fresh, pooled plasma for the culture medium ...

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“…When this transam ination is coupled with PC reductase, orni thine also serves as a precursor of proline. plasma ornithine [Berson et al, 1976]. Addi tional evidence suggesting that a large amount of ornithine goes through the OAT pathway is found in PC dehydrogenase defi ciency in which the plasma proline concen tration is several-fold higher than that in pro line oxidase deficiency [Scriver, 1978], We may postulate that in the latter, the metabo lism of PC is not affected whereas in the former the PC derived from ornithine could only be converted to proline via PC reductase [, Simila, 1970], and thereby contributes to the proline pool.…”

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confidence: 99%

Regulation of Ornithine Metabolism

Shih¹

1981

Enzyme

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Plasma amino-acids in hereditary retinal disease. Ornithine, lysine, and taurine.

Cited by 59 publications

References 11 publications

Cloning and expression of a cDNA encoding the transporter of taurine and beta-alanine in mouse brain.

Cloning and expression of a cDNA encoding the transporter of taurine and beta-alanine in mouse brain.

Gyrate atrophy of the choroid and retina: deficiency of ornithine aminotransferase in transformed lymphocytes.

Regulation of Ornithine Metabolism

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