| Co-Investigator(Kenkyū-buntansha) |
山田 裕一 愛知県心身障害者コロニー, 発達障害研究所・生化学部, 研究員
GOTO Haruko Department of Biochemistry, Institute for Developmental Research, Aichi Prefectu, 発達障害研究所・生化学部, 研究助手
YAMADA Yasukazu Department of Biochemistry, Institute for Developmental Research, Aichi Prefectu
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| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
There are multiple tissue specific AMP deaminase isozymes in human. They are erythrocyte type ( <E_1> , <E_2> ), liver type (L) and muscle type (M). The deficiency of isozyme M was reported in 1978 by Fishbein et al.
We have found six individuals with complete deficiency of erythrocyte AMP deaminase. They are all healthy and have no hematological disorders. Serum uric acid levels were slightly lower comparing to the control. In order to exclude an erythrocyte glycolysis defect, 2,3-diphosphoglycerate (DPG) and ATP contents of the erythrocyte from the deficient individuals were determined. There was no distinct difference in DPG content from the control value. ATP levels were apparently higher in the AMP deaminase deficient cells; on average, the level is 50 % higher in the deficient cells. Metabolic studies indicated the slower degradation of adenine nucleotide in deficient cells and these deficient cells are rather more efficient in maintaining the adenine nucleotide pool. The deficien
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cy is only in erythrocyte type isozyme; monomuclear cells and platelets, which have isozyme L, show normal level of AMP deaminase activity. Of the known AMP deaminase isozymes, <E_2> is very similar to <E_1> in kinetic and immnological properties. The subjects with complete deficiency of erythrocyte AMP deaminase lack both <E_1> and <E_2> . These results indicate that these two isozymes are the product of the same gene. To study on the molecular mechanism of this enzyme deficiency in future, EB virus transformed B-lymphoblast cell lines were established from the deficient individuals. Normal cell lines express erythrocyte type isozyme, but the cell lines derived from the deficient individuals do not express erythrocyte type isozyme. From the familiar study, it is evident the deficiency is inherited as an autosomal recessive trait. The frequency of the mutant gene is surprisingly high, one heterozygote in about 30 of the population in Japan, Seoul and Taipei, resulting in one complete deficiency in about 3,600 population. However, according to the personal communications no heterozygote was found in Belgium and Israel. Therfore, this deficiency may be only common in oriental people. Less
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