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A Study of the Inheritance and Properties of an Electrophoretic Variant of NADH‐Methaemoglobin Reductase Associated with Congenital Methaemoglobinaemia
Author(s) -
West C. A.
Publication year - 1972
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1972.tb08881.x
Subject(s) - methemoglobin , reductase , enzyme , heterozygote advantage , electrophoresis , biochemistry , red cell , biology , microbiology and biotechnology , chemistry , hemoglobin , medicine , gene , allele
Summary. Further investigation on the patient previously reported and on his family are described. It is shown that in this patient the disease is the result of a doubly heterozygous state in which both an electrophoretically slow enzyme variant (m a ) and small amounts of electrophoretically normal NADH‐methaemoglobin reductase are present. Electrophoretic and kinetic studies showed that the abnormal enzyme variant m a possessed a significantly reduced capacity for binding NADH compared with the normal enzyme, which was found to consist of two distinct components when studied in an electrophoretic system incorporating NADH. The variant m a appeared to consist of only the minor of these components. The mother of the patient, and 13 other family members were identified as heterozygotes after electrophoretic analysis of haemoglobin free red cell extracts. The assay of red cell NADH‐methaemoglobin reductase in all the electrophoretically confirmed heterozygotes demonstrated the considerable overlap of their enzyme levels with the normal range, and therefore the inadvisability of utilizing NADH‐methaemoglobin reductase level alone as the criterion of the heterozygous state.