Abstract
The gene for maleylacetoacetate isomerase (MAAI) (EC 5.2.1.2) was the last gene in the mammalian phenylalanine/tyrosine catabolic pathway to be cloned. We have isolated the human and murine genes and determined their genomic structure. The human gene spans a genomic region of ~10 kb, has 9 exons ranging from 50 to 528 bp in size, and was mapped to 14q24.3-14q31.1 using fluorescence in situ hybridization. The complete catabolic pathway of phenylalanine/tyrosine is normally restricted to liver and kidney, but the maleylacetoacetate isomerase gene is expressed ubiquitously. This suggests a possible second role for the MAAI protein different from phenylalanine/tyrosine catabolism. We have searched for mutations in the maleylacetoacetate isomerase gene in four cases of unexplained severe liver failure in infancy with clinical similarities to hereditary tyrosinemia type I (pseudotyrosinemia). Several amino acid changes were identified, but all were found to retain MAAI activity and thus represent protein polymorphisms. We conclude that MAA deficiency is not a common cause of the pseudotyrosinemic phenotype.
Original language | English (US) |
---|---|
Pages (from-to) | 263-269 |
Number of pages | 7 |
Journal | Genomics |
Volume | 58 |
Issue number | 3 |
DOIs | |
State | Published - Jun 15 1999 |
Keywords
- Gene structure
- Liver failure
- Maleylacetoacetate isomerase
- Pseudotyrosinemia
ASJC Scopus subject areas
- Genetics