| Autor: |
Shirabe, Komei, Yubisui, Toshitsugu, Takeshita, Masazumi |
| Jazyk: |
angličtina |
| Rok vydání: |
1995 |
| Předmět: |
|
| Zdroj: |
山口医科大学紀要. 42(3-4):49-53 |
| Popis: |
Hereditary methemoglobinemia is an autosomal recessive disorder caused by a deficiency of NADH-cytochrome b5 reductase. In most cases enzyme deficiency occurs in red cells and symptom is only cyanosis due to elevated methemoglobin (type I). In about 10% of the cases deficiency is demonstrated in all the examined tissues and is accompanied by methemoglobinemia and severe neurological disorders (type II). Gene analyses of five independent families with I disease showed that point mutations leading to amino acid substitutions occur in all cases. Mutations found in three patients of type II disease were a point mutation, a deletion of 3 bases that leads to one amino acid deletion, and a mutation of splicing acceptor site of exon 9. Charasterization of recombinant type I and type II mutant enzymes syowed that type Ienzymes retained high enzyme activity but were unstable, wherews type II enzymes had low catalytic ability. Mutations in type I disease on three dimensional styucture of the enzyme residein the marginal portion of the enzyme that seem to participate in maintaining the enzyme structure, explain low catalytic efficiency of mutants. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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