Glycine cleavage system in ketotic hyperglycinemia: a reduction of H-protein activity
| Autor: | Tsuruo Satoh, Tsugutoshi Aoki, K. Metoki, Tadashi Kawakami, Koichi Hiraga, Kuniaki Narisawa, Kiyoshi Hayasaka, Hiroshi Akamatsu, Keiya Tada, Hiraku Tateda, Noritake Matsuo |
|---|---|
| Rok vydání: | 1982 |
| Předmět: |
medicine.medical_specialty
medicine.medical_treatment Methylmalonic acidemia Glycine Cleavage (embryo) Glycine Decarboxylase Complex H-Protein Low-protein diet Internal medicine medicine Ketotic hyperglycinemia Humans Propionic acidemia Glycine cleavage system Chemistry Infant Metabolic acidosis Ketosis medicine.disease Glycine Dehydrogenase (Decarboxylating) Endocrinology Liver Pediatrics Perinatology and Child Health Female Amino Acid Oxidoreductases Acidosis Carrier Proteins |
| Zdroj: | Pediatric research. 16(1) |
| ISSN: | 0031-3998 |
| Popis: | Glycine cleavage activity was compared in the livers from three cases of ketotic hyperglycinemia (two cases of propionic acidemia and one case of methylmalonic acidemia) and three controls. In one case of propionic acidemia, glycine cleavage activity (5.2 nmole/mg protein/hr) was normal in the liver obtained at biopsy when the patient was well controlled by the treatment with low protein diet (0.8 g/kg/day) and the level of serum glycine was lowered to normal. In the two other cases of ketotic hyperglycinemia, glycine cleavage activity was significantly reduced in the liver obtained at autopsy when the patients died in the state of metabolic acidosis. Its activity in the liver of one case of propionic acidemia (0.7 nmole/mg protein/hr) was 6–26% of that in controls (2.7–10.8 nmole/mg protein/hr), and 2–7% in a case of methylmalonic acidemia (0.2 nmole/mg protein/hr). Analysing of the individual components of the glycine cleavage system, a marked decrease in the activity of H-protein was revealed in the livers of the both patients; it (0.2 nmole/mg protein/ hr) was only 3–4% of that in controls (4.9–6.3 nmole/mg protein/ hr). These findings suggest that the reduction of the glycine cleavage system in the liver of ketotic hyperglycinemia occurs secondarily as speculated previously and is caused mainly by a decrease of H-protein activity. Speculation: The reduction of glycine cleavage activity in ketotic hyperglycinemia may be caused at first by an inactivation of H-protein. Subsequently the activities of other components of the glycine cleavage system may be decreased. |
| Databáze: | OpenAIRE |
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