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Decreased transport of ornithine across the inner mitochondrial membrane as a cause of hyperornithinaemia
Author(s) -
Hommes F. A.,
Ho C. K.,
Roesel R. A.,
Coryell M. E.,
Gordon B. A.
Publication year - 1982
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1007/bf01799753
Subject(s) - fibroblast , ornithine , inner mitochondrial membrane , cytoplasm , mitochondrion , digitonin , inner membrane , chemistry , biochemistry , membrane , biology , in vitro , amino acid , arginine
Hyperornithinaemia due to a transport defect of ornithine across the inner mitochondrial membrane was demonstrated in three patients by measuring ornithine uptake by fibroblast mitochondria. Particulate compartments and soluble cytoplasm of fibroblasts were separated by a slight modification of the digitonin method of Zuurendonk and Tager. Patient's fibroblast pellet fraction contained significantly less radioactivity than control fibroblast pellet fraction after incubation of fibroblasts with [ 14 C]‐ornithine. Since neither of the patients was deficient in ornithine‐δ‐oxoacid aminotransferase, we concluded that in these hyperornithinaemia patients a defect exists for transport of ornithine across the inner mitochondrial membrane. The exact nature of this transport defect remains to be elucidated.