Distinct behavior of mutant triosephosphate isomerase in hemolysate and in isolated form: molecular basis of enzyme deficiency

• Published in: Blood Vol. 98; no. 10; pp. 3106 - 3112
• Main Authors: Orosz, Ferenc, Oláh, Judit, Alvarez, Marco, Keserű, György M., Szabó, Beáta, Wágner, Gábor, Kovári, Zoltán, Horányi, Margit, Baróti, Klára, Martial, Joseph A., Hollán, Susan, Ovádi, Judit
• Format: Journal Article Web Resource
• Language: English
• Published: Washington, DC Elsevier Inc 15.11.2001; The Americain Society of Hematology; American Society of Hematology
• Subjects: Adult; Amino Acid Substitution; Anemia, Hemolytic, Congenital Nonspherocytic - blood; Anemia, Hemolytic, Congenital Nonspherocytic - enzymology; Anemia, Hemolytic, Congenital Nonspherocytic - genetics; Anemia, Hemolytic, Congenital Nonspherocytic/blood/enzymology/genetics; Anemias. Hemoglobinopathies; Biochemistry, biophysics & molecular biology; Biochimie, biophysique & biologie moléculaire; Biological and medical sciences; Brain - cytology; Child, Preschool; Circular Dichroism; Codon, Nonsense; Codon, Terminator; Computer Simulation; Dimerization; Diseases of red blood cells; Erythrocyte Membrane - metabolism; Female; Great Britain; Hematologic and hematopoietic diseases; Heterozygote; Humans; Hungary; Life sciences; Male; Medical sciences; Microtubules - metabolism; Models, Molecular; Mutagenesis, Site-Directed; Mutation, Missense; Point Mutation; Protein Binding; Protein Conformation; purification/metabolism; Recombinant Fusion Proteins - metabolism; Sciences du vivant; Triose-Phosphate Isomerase - chemistry; Triose-Phosphate Isomerase - deficiency; Triose-Phosphate Isomerase - genetics; Triose-Phosphate Isomerase - isolation & purification; Triose-Phosphate Isomerase - metabolism; Triose-Phosphate Isomerase/chemistry/deficiency/genetics/isolation; United Kingdom; Human; Nervous system diseases; Intramolecular oxidoreductases; Enzyme; Pathogenesis; Deficiency; Red blood cell; Metabolic diseases; Hemopathy; Enzymopathy; Triose-phosphate isomerase; Genetic disease; Case study; Hemolytic anemia; Isomerases; Enzymatic activity; Gene; Genetics; EC 5.3.1.1; Mutation
• ISSN: 0006-4971; 1528-0020; 1528-0020
• DOI: 10.1182/blood.V98.10.3106

In a Hungarian family with severe decrease in triosephosphate isomerase (TPI) activity, 2 germ line–identical but phenotypically differing compound heterozygote brothers inherited 2 independent (Phe240Leu and Glu145stop codon) mutations. The kinetic, thermodynamic, and associative properties of the recombinant human wild-type and Phe240Leu mutant enzymes were compared with those of TPIs in normal and deficient erythrocyte hemolysates. The specific activity of the recombinant mutant enzyme relative to the wild type was much higher (30%) than expected from the activity (3%) measured in hemolysates. Enhanced attachment of mutant TPI to erythrocyte inside-out vesicles and to microtubules of brain cells was found when the binding was measured with TPIs in hemolysate. In contrast, there was no difference between the binding of the recombinant wild-type and Phe240Leu mutant enzymes. These findings suggest that the missense mutation by itself is not enough to explain the low catalytic activity and “stickiness” of mutant TPI observed in hemolysate. The activity of the mutant TPI is further reduced by its attachment to inside-out vesicles or microtubules. Comparative studies of the hemolysate from a British patient with Glu104Asp homozygosity and with the platelet lysates from the Hungarian family suggest that the microcompartmentation of TPI is not unique for the hemolysates from the Hungarian TPI-deficient brothers. The possible role of cellular components, other than the mutant enzymes, in the distinct behavior of TPI in isolated form versus in hemolysates from the compound heterozygotes and the simple heterozygote family members is discussed.