标题：Characterization of residual enzyme activity in fibroblasts from patients with adenosine deaminase deficiency and combined immunodeficiency: evidence for a mutant enzyme
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1976
卷号：73
期号：1
页码：213-217
DOI：10.1073/pnas.73.1.213
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：A proportion of patients suffering from the autosomal recessive form of severe combined immunodeficiency have an inherited deficiency of adenosine deaminase (EC 3.5.4.4 ; adenosine aminohydrolase) (erythrocyte isoenzyme). We have, however, found residual adenosine deaminase activity in fibroblasts derived from four such patients. The enzyme responsible for this activity is biochemically homologous with the high-molecular-weight tissue isoenzyme of adenosine deaminase found in normal fibroblasts and tissues other than erythrocytes. The residual adenosine deaminase has an altered electrophoretic mobility, increased heat stability as compared to normals, and can be detected in fibroblasts of obligate heterozygotes. Our previous studies have indicated that the tissue and erythrocyte adenosine deaminase isoenzymes contain a common catalytic unit controlled by the gene affected in severe combined immunodeficiency with absent adenosine deaminase (erythrocyte isoenzyme). This residual adenosine deaminase therefore represents, most likely, a "mutant" enzyme in fibroblasts of patients with severe combined immunodeficiency. The data support the hypothesis that, in these patients, severe combined immunodeficiency is due to a mutation at the adenosine deaminase locus.
