scholarly journals Alteration of substrate specificity by a naturally-occurring aldolase B mutation (Ala337→Val) in fructose intolerance

1999 ◽  
Vol 340 (1) ◽  
pp. 321-327 ◽  
Author(s):  
Peter RELLOS ◽  
Manir ALI ◽  
Michel VIDAILHET ◽  
Jurgen SYGUSCH ◽  
Timothy M. COX
Keyword(s):  
Novel Mutation ◽  
Wild Type ◽  
Hereditary Fructose Intolerance ◽  
Fluorescence Studies ◽  
Naturally Occurring ◽  
C Terminus ◽  
Fructose Intolerance ◽  
Michaelis Constants ◽  
Specific Activities ◽  
Aldolase B

A molecular analysis of human aldolase B genes in two newborn infants and a 4-year-old child with hereditary fructose intolerance, the offspring of a consanguineous union, has identified the novel mutation Ala337 → Val in homozygous form. This mutation was also detected independently in two other affected individuals who were compound heterozygotes for the prevalent aldolase B allele, Ala149 → Pro, indicating that the mutation causes aldolase B deficiency. To test for the effect of the mutation, catalytically active wild-type human aldolase B and the Val337 variant enzyme were expressed in Escherichia coli. The specific activities of the wild-type recombinant enzyme were 4.8 units/mg and 4.5 units/mg towards fructose 1,6-bisphosphate (FBP) and fructose 1-phosphate (F-1-P) as substrates with Michaelis constants of 4 μM and 2.4 mM respectively. The specific activities of purified tetrameric Val337 aldolase B, which affects an invariant residue in the C-terminal region, were 4.2 units/mg and 2.6 units/mg towards FBP and F-1-P as substrates respectively; the corresponding Michaelis constants were 22 μM and 24 mM. The FBP-to-F-1-P substrate activity ratios were 0.98 and 1.63 for wild-type and Val337 variant enzymes respectively. The Val337 mutant aldolase had an increased susceptibility to proteolytic cleavage in E. coli and rapidly lost activity on storage. Comparative CD determinations showed that the Val337 protein had a distinct thermal denaturation profile with markedly decreased enthalpy, indicating that the mutant protein is partly unfolded. The undegraded mutant had preferentially decreased affinity and activity towards its specific F-1-P substrate and maintained appreciable activity towards FBP. In contrast, fluorescence studies of the mutant showed an increased binding affinity for products of the aldolase reaction, indicating a role for the C-terminus in mediating product release. These findings in a rare but widespread naturally occurring mutant implicate the C-terminus in the activity of human aldolase B towards its specific substrates and demonstrate its role in maintaining the overall stability of the enzyme tetramer.

scholarly journals Functional and molecular modelling studies of two hereditary fructose intolerance-causing mutations at arginine 303 in human liver aldolase

2000 ◽  
Vol 350 (3) ◽  
pp. 823-828 ◽  
Author(s):  
Rita SANTAMARIA ◽  
Gabriella ESPOSITO ◽  
Luigi VITAGLIANO ◽  
Vincenza RACE ◽  
Immacolata PAGLIONICO ◽  
...  
Keyword(s):  
Homology Modelling ◽  
Three Dimensional ◽  
Catalytic Efficiency ◽  
Dimensional Structure ◽  
Kinetic Properties ◽  
Wild Type ◽  
Hereditary Fructose Intolerance ◽  
Fructose Intolerance ◽  
Aldolase B ◽  
Fructose 1,6 Bisphosphate

We have identified a novel hereditary fructose intolerance mutation in the aldolase B gene (i.e. liver aldolase) that causes an arginine-to-glutamine substitution at residue 303 (Arg303 → Gln). We previously described another mutation (Arg303 → Trp) at the same residue. We have expressed the wild-type protein and the two mutated proteins and characterized their kinetic properties. The catalytic efficiency of protein Gln303 is approx. 1/100 that of the wild-type for substrates fructose 1,6-bisphosphate and fructose 1-phosphate. The Trp303 enzyme has a catalytic efficiency approx. 1/4800 that of the wild-type for fructose 1,6-bisphosphate; no activity was detected with fructose 1-phosphate. The mutation Arg303 → Trp thus substitution impairs enzyme activity more than Arg303 → Gln. Three-dimensional models of wild-type, Trp303 and Gln303 aldolase B generated by homology-modelling techniques suggest that, because of its larger size, tryptophan exerts a greater deranging effect than glutamine on the enzyme's three-dimensional structure. Our results show that the Arg303 → Gln substitution is a novel mutation causing hereditary fructose intolerance and provide a functional demonstration that Arg303, a conserved residue in all vertebrate aldolases, has a dominant role in substrate binding during enzyme catalysis.

scholarly journals Daily Fructose Traces Intake and Liver Injury in Children with Hereditary Fructose Intolerance

Nutrients ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2397 ◽  
Author(s):  
Di Dato ◽  
Spadarella ◽  
Puoti ◽  
Caprio ◽  
Pagliardini ◽  
...  
Keyword(s):  
Liver Injury ◽  
Genetic Disorder ◽  
Liver Steatosis ◽  
Daily Intake ◽  
Young Patients ◽  
Hereditary Fructose Intolerance ◽  
Fructose Intake ◽  
Fructose Intolerance ◽  
Carbohydrate Deficient Transferrin ◽  
Aldolase B

Background: Hereditary fructose intolerance (HFI) is a rare genetic disorder of fructose metabolism due to aldolase B enzyme deficiency. Treatment consists of fructose, sorbitol, and sucrose (FSS)-free diet. We explore possible correlations between daily fructose traces intake and liver injury biomarkers on a long-term period, in a cohort of young patients affected by HFI. Methods: Patients’ clinical data and fructose daily intake were retrospectively collected. Correlations among fructose intake, serum alanine aminotransferase (ALT) level, carbohydrate-deficient transferrin (CDT) percentage, liver ultrasonography, genotype were analyzed. Results: We included 48 patients whose mean follow-up was 10.3 ± 5.6 years and fructose intake 169 ± 145.4 mg/day. Eighteen patients had persistently high ALT level, nine had abnormal CDT profile, 45 had signs of liver steatosis. Fructose intake did not correlate with ALT level nor with steatosis severity, whereas it correlated with disialotransferrin percentage (R2 0.7, p < 0.0001) and tetrasialotransferrin/disialotransferrin ratio (R2 0.5, p = 0.0001). p.A150P homozygous patients had lower ALT values at diagnosis than p.A175D variant homozygotes cases (58 ± 55 IU/L vs. 143 ± 90 IU/L, p = 0.01). Conclusion: A group of HFI patients on FSS-free diet presented persistent mild hypertransaminasemia which did not correlate with fructose intake. Genotypes may influence serum liver enzyme levels. CDT profile represents a good marker to assess FSS intake.

scholarly journals Fructosuria and recurrent hypoglycemia in a patient with a novel c.1693T>A variant in the 3′ untranslated region of the aldolase B gene

2019 ◽  
Vol 7 ◽  
pp. 2050313X1882309
Author(s):  
Martha Catalina Morales-Alvarez ◽  
Maria Laura Ricardo-Silgado ◽  
Hernan Nicolas Lemus ◽  
Deyanira González-Devia ◽  
Carlos O Mendivil
Keyword(s):  
Untranslated Region ◽  
Stop Codon ◽  
Glucose Monitoring ◽  
Repeated Measurements ◽  
Hereditary Fructose Intolerance ◽  
Dietary Fructose ◽  
Fructose Intolerance ◽  
Exon 9 ◽  
Aldolase B ◽  
Hydrolysis Of

Hereditary fructose intolerance, caused by mutations in the ALDOB gene, is an unusual cause of hypoglycemia. ALDOB encodes the enzyme aldolase B, responsible for the hydrolysis of fructose 1-phosphate in the liver. Here, we report the case of a 33-year-old female patient who consulted due to repetitive episodes of weakness, dizziness and headache after food ingestion. An ambulatory 72-h continuous glucose monitoring revealed multiple short hypoglycemic episodes over the day. After biochemical exclusion of other endocrine causes of hypoglycemia, hereditary fructose intolerance seemed a plausible diagnosis. Repeated measurements of urinary fructose revealed pathologic fructosuria, but genetic testing for the three most common mutations in ALDOB resulted negative. We decided to perform complete Sanger sequencing of the ALDOB gene and encountered a variant consisting of a T>A substitution in position 1963 of the ALDOB transcript (c.1693T>A). This position is located within the 3′ untranslated region of exon 9, 515 nucleotides downstream the stop codon. After complete withdrawal of dietary fructose and sucrose, the patient presented no new hypoglycemic episodes.

Mutation of aldolase B genes in hereditary fructose intolerance

The Lancet ◽  
1990 ◽  
Vol 335 (8693) ◽  
pp. 856 ◽  
Author(s):  
M. De Souza ◽  
R. Lindeman ◽  
F. Volpato ◽  
R.J. Trent ◽  
R. Kamath
Keyword(s):  
Hereditary Fructose Intolerance ◽  
Fructose Intolerance ◽  
Aldolase B

scholarly journals HEREDITARY FRUCTOSE INTOLERANCE IN A PEDIATRIC CONTEXT

2018 ◽  
Vol 3 (5) ◽  
pp. 66-74
Author(s):  
Lucas Leimig Telles Parente ◽  
Rodrigo Emmanuel Leimig Telles Parente ◽  
Maria Valéria Leimig Telles ◽  
Maria das Graças Nascimento Silva
Keyword(s):  
Hereditary Fructose Intolerance ◽  
Electronic Library ◽  
Fructose Intolerance ◽  
The Subject ◽  
Aldolase B ◽  
Nutritional Monitoring ◽  
Carbohydrate Intolerance ◽  
Publication Period ◽  
Made In

Carbohydrate intolerance is relatively common in childhood, but its diagnosis and management are still quite precarious. Hereditary fructose intolerance (HFI) is an autosomal recessive disease that results in deficiency of the enzyme aldolase B, which contributes to the onset of gastrointestinal and metabolic symptoms, triggered by the ingestion of foods high in fructose, sucrose or sorbitol. Methodology: For the accomplishment of such a study a search of the literature was done from August to September of the year 2018 with publication period of a maximum of 10 years. The theoretical reference was elaborated through the collection of relevant scientific articles on the subject, made in the electronic databases: Scientific Electronic Library Online (SciELO), Pubmed, EBSCOhost and CAPES, from descriptors generated by DeCS: "Fructose Intolerance"; "Child" and its correspondents in English. Thus, 81 articles were obtained and, from the title of the literature and its abstracts, were used. 19 Ademias, articles that were related to the topics covered in this study or whose sample was not composed by humans were also discarded. The diagnosis of HFI is based on the suggestive clinical picture initiated after the ingestion of the fructose, sucrose and sorbitol already mentioned, associated with the use of invasive and noninvasive examinations, but the confirmation is based on the response to the improvement of the symptoms after the restriction of the ingestion of such food, which constitutes the best therapy. Conclusion: Based on the consequences of inadequate management of HFI, it is of fundamental importance that the affected children have an early diagnosis, associated with an adequate nutritional monitoring, which enables an improvement in the quality of life of these individuals, besides preventing important repercussions such as renal and hepatic impairment. Keywords: Hereditary Intolerance to Fructose, Child and Diet

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