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. 1989 Mar;44(3):344–352.

Gyrate atrophy of the choroid and retina: characterization of mutant ornithine aminotransferase and mechanism of response to vitamin B6.

N G Kennaway 1, L Stankova 1, M K Wirtz 1, R G Weleber 1
PMCID: PMC1715442  PMID: 2916580

Abstract

The purpose of this study was to characterize the mutant enzyme in nine patients with gyrate atrophy of the choroid and retina associated with ornithine aminotransferase (OAT) deficiency, to elucidate the mechanism of response to pyridoxine in four pyridoxine-responsive patients, and to determine the extent of genetic heterogeneity in both groups of patients. We have measured the apparent Km for pyridoxal phosphate (PLP) in fibroblast mitochondria and the heat stability of OAT at 45 degrees C in the presence and absence of PLP, using a sensitive radiochemical assay. The apparent Km for PLP was higher in pyridoxine-responsive patients than in nonresponsive patients whose apparent Km for PLP was normal. In contrast, the apparent Km for ornithine was normal in the seven patients studied. Surprisingly, the responsive patient with mildest clinical disease had the highest Km for PLP. However, she had the most stable enzyme, which presumably contributed to her milder phenotype. Western blot analyses of mitochondrial proteins, using antibody to human OAT, indicated clearly detectable OAT protein in pyridoxine-responsive patients and in two of five nonresponders, but low or undetectable levels in the other three patients. These data clarify the mechanism of pyridoxine response and indicate heterogeneity within as well as between the pyridoxine-responsive and the nonresponsive patients with gyrate atrophy.

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Selected References

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  1. Hayasaka S., Saito T., Nakajima H., Takaku Y., Shiono T., Mizuno K., Ohmura K., Tada K. Gyrate atrophy with hyperornithinaemia: different types of responsiveness to vitamin B6. Br J Ophthalmol. 1981 Jul;65(7):478–483. doi: 10.1136/bjo.65.7.478. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Inana G., Hotta Y., Zintz C., Takki K., Weleber R. G., Kennaway N. G., Nakayasu K., Nakajima A., Shiono T. Expression defect of ornithine aminotransferase gene in gyrate atrophy. Invest Ophthalmol Vis Sci. 1988 Jul;29(7):1001–1005. [PubMed] [Google Scholar]
  3. Kaiser-Kupfer M. I., Valle D., Bron A. J. Clinical and biochemical heterogeneity in gyrate atrophy. Am J Ophthalmol. 1980 Feb;89(2):219–222. doi: 10.1016/0002-9394(80)90114-2. [DOI] [PubMed] [Google Scholar]
  4. Kennaway N. G., Weleber R. G., Buist N. R. Gyrate atrophy of the choroid and retina with hyperornithinemia: biochemical and histologic studies and response to vitamin B6. Am J Hum Genet. 1980 Jul;32(4):529–541. [PMC free article] [PubMed] [Google Scholar]
  5. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  6. Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
  7. Litwack G., Rosenfield S. Coenzyme dissociation, a possible determinant of short half-life of inducible enzymes in mammalian liver. Biochem Biophys Res Commun. 1973 May 1;52(1):181–188. doi: 10.1016/0006-291x(73)90971-6. [DOI] [PubMed] [Google Scholar]
  8. Ohura T., Kominami E., Tada K., Katunuma N. Crystallization and properties of human liver ornithine aminotransferase. J Biochem. 1982 Dec;92(6):1785–1792. doi: 10.1093/oxfordjournals.jbchem.a134108. [DOI] [PubMed] [Google Scholar]
  9. Rhead W. J., Tanaka K. Demonstration of a specific mitochondrial isovaleryl-CoA dehydrogenase deficiency in fibroblasts from patients with isovaleric acidemia. Proc Natl Acad Sci U S A. 1980 Jan;77(1):580–583. doi: 10.1073/pnas.77.1.580. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Shih V. E., Berson E. L., Mandell R., Schmidt S. Y. Ornithine ketoacid transaminase deficiency in gyrate atrophy of the choroid and retina. Am J Hum Genet. 1978 Mar;30(2):174–179. [PMC free article] [PubMed] [Google Scholar]
  11. Simell O., Takki K. Raised plasma-ornithine and gyrate atrophy of the choroid and retina. Lancet. 1973 May 12;1(7811):1031–1033. doi: 10.1016/s0140-6736(73)90667-3. [DOI] [PubMed] [Google Scholar]
  12. Sipilä I., Simell O., O'Donnell J. J. Gyrate atrophy of the choroid and retina with hyperornithinemia: characterization of mutant liver L-ornithine:2-oxoacid aminotransferase kinetics. J Clin Invest. 1981 Jun;67(6):1805–1807. doi: 10.1172/JCI110222. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Towbin H., Staehelin T., Gordon J. Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications. Proc Natl Acad Sci U S A. 1979 Sep;76(9):4350–4354. doi: 10.1073/pnas.76.9.4350. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Weleber R. G., Kennaway N. G. Clinical trial of vitamin B6 for gyrate atrophy of the choroid and retina. Ophthalmology. 1981 Apr;88(4):316–324. doi: 10.1016/s0161-6420(81)35035-0. [DOI] [PubMed] [Google Scholar]
  15. Weleber R. G., Wirtz M. K., Kennaway N. G. Gyrate atrophy of the choroid and retina: clinical and biochemical heterogeneity and response to vitamin B6. Birth Defects Orig Artic Ser. 1982;18(6):219–230. [PubMed] [Google Scholar]
  16. Wirtz M. K., Kennaway N. G., Weleber R. G. Heterogeneity and complementation analysis of fibroblasts from vitamin B6 responsive and non-responsive patients with gyrate atrophy of the choroid and retina. J Inherit Metab Dis. 1985;8(2):71–74. doi: 10.1007/BF01801668. [DOI] [PubMed] [Google Scholar]
  17. Wong P. T., McGeer E. G., McGeer P. L. A sensitive radiometric assay for ornithine aminotransferase: regional and subcellular distributions in rat brain. J Neurochem. 1981 Feb;36(2):501–505. doi: 10.1111/j.1471-4159.1981.tb01620.x. [DOI] [PubMed] [Google Scholar]

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