Co-synthesis of Human δ-Aminolevulinate Dehydratase (ALAD) Mutants with the Wild-type Enzyme in Cell-free System—Critical Importance of Conformation on Enzyme Activity—

Inoue, Rikako; Akagi, Reiko

doi:10.3164/jcbn.2008035

Cited by 6 publications

(4 citation statements)

References 27 publications

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“…The wild-type enzyme exists as a high-activity homooctamer, but alternative lower-activity hexamer assemblies have been found [51]. In fact, naturally occurring ALAD porphyria-associated human variants have been shown to have an increased susceptibility to hexamer-stabilizing inhibitors.…”

Section: Resultsmentioning

confidence: 99%

“…Delta-aminolevulinic acid dehydratase (ALADH), encoded by the ALAD gene in humans, catalyzes the first common step in heme and other tetrapyrrole biosynthesis [ 49 ] and has also been observed to interact with the proteasome [ 50 ]. The wild-type enzyme exists as a high-activity homooctamer, but alternative lower-activity hexamer assemblies have been found [ 51 ]. In fact, naturally occurring ALAD porphyria-associated human variants have been shown to have an increased susceptibility to hexamer-stabilizing inhibitors.…”

Section: Resultsmentioning

confidence: 99%

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A framework for application of metabolic modeling in yeast to predict the effects of nsSNV in human orthologs

et al. 2014

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BackgroundWe have previously suggested a method for proteome wide analysis of variation at functional residues wherein we identified the set of all human genes with nonsynonymous single nucleotide variation (nsSNV) in the active site residue of the corresponding proteins. 34 of these proteins were shown to have a 1:1:1 enzyme:pathway:reaction relationship, making these proteins ideal candidates for laboratory validation through creation and observation of specific yeast active site knock-outs and downstream targeted metabolomics experiments. Here we present the next step in the workflow toward using yeast metabolic modeling to predict human metabolic behavior resulting from nsSNV.ResultsFor the previously identified candidate proteins, we used the reciprocal best BLAST hits method followed by manual alignment and pathway comparison to identify 6 human proteins with yeast orthologs which were suitable for flux balance analysis (FBA). 5 of these proteins are known to be associated with diseases, including ribose 5-phosphate isomerase deficiency, myopathy with lactic acidosis and sideroblastic anaemia, anemia due to disorders of glutathione metabolism, and two porphyrias, and we suspect the sixth enzyme to have disease associations which are not yet classified or understood based on the work described herein.ConclusionsPreliminary findings using the Yeast 7.0 FBA model show lack of growth for only one enzyme, but augmentation of the Yeast 7.0 biomass function to better simulate knockout of certain genes suggested physiological relevance of variations in three additional proteins. Thus, we suggest the following four proteins for laboratory validation: delta-aminolevulinic acid dehydratase, ferrochelatase, ribose-5 phosphate isomerase and mitochondrial tyrosyl-tRNA synthetase. This study indicates that the predictive ability of this method will improve as more advanced, comprehensive models are developed. Moreover, these findings will be useful in the development of simple downstream biochemical or mass-spectrometric assays to corroborate these predictions and detect presence of certain known nsSNVs with deleterious outcomes. Results may also be useful in predicting as yet unknown outcomes of active site nsSNVs for enzymes that are not yet well classified or annotated.ReviewersThis article was reviewed by Daniel Haft and Igor B. Rogozin.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

A framework for application of metabolic modeling in yeast to predict the effects of nsSNV in human orthologs

et al. 2014

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“…The enzyme functions as a homooctomer, and requires an intact sulfhydryl group and zinc for activity. Mutations associated with ALAD porphyria favor formation of the less active hexamer [26][27][28]. Lead inhibits ALAD activity by displacing the catalytically important zinc [29], leading to urinary ALA and coproporphyrin excretion.…”

Section: Physiological Heme Biosynthesismentioning

confidence: 99%

Heme biosynthesis and the porphyrias

Phillips

2019

Molecular Genetics and Metabolism

151

139

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Porphyrias, is a general term for a group of metabolic diseases that are genetic in nature. In each specific porphyria the activity of specific enzymes in the heme biosynthetic pathway is defective and leads to accumulation of pathway intermediates. Phenotypically, each disease leads to either neurologic and/or photo-cutaneous symptoms based on the metabolic intermediate that accumulates. In each porphyria the distinct patterns of these substances in plasma, erythrocytes, urine and feces are the basis for diagnostically defining the metabolic defect underlying the clinical observations. Porphyrias may also be classified as either erythropoietic or hepatic, depending on the principal site of accumulation of pathway intermediates. The erythropoietic porphyrias are congenital erythropoietic porphyria (CEP), and erythropoietic protoporphyria (EPP). The acute hepatic porphyrias include ALA dehydratase deficiency porphyria, acute intermittent porphyria (AIP), hereditary coproporphyria (HCP) and variegate porphyria (VP). Porphyria cutanea tarda (PCT) is the only porphyria that has both genetic and/or environmental factors that lead to reduced activity of uroporphyrinogen decarboxylase in the liver. Each of the 8 enzymes in the heme biosynthetic pathway have been associated with a specific porphyria (Table 1). Mutations affecting the erythroid form of ALA synthase (ALAS2) are most commonly associated with X-linked sideroblastic anemia, however, gain-of-function mutations of ALAS2 have also been associated with a variant form of EPP. This overview does not describe the full clinical spectrum of the porphyrias, but is meant to be an overview of the biochemical steps that are required to make heme in both erythroid and non-erythroid cells.

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“…ALAD activity is inhibited by many chemicals or compounds, such as lead or succinylacetone. Clinical ADP symptoms resemble those characteristics which are connected to other acute hepatic porphyrias but present no photosensitivity or skin lesions [16,28,29].…”

Section: Ala Dehydratase Deficiency Porphyria (Adp Doss Porphyria)mentioning

confidence: 99%

Clinical, Biochemical and Molecular Characteristics of the Main Types of Porphyria

2015

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Porphyrias are diverse disorders that arise from various inherited enzyme defects in the heme biosynthesis pathway, except for porphyria cutanea tarda (PCT), in which the enzyme deficiency in most cases is acquired. The biosynthetic blocks resulting from the defective enzymes are largely expressed either in the liver or bone marrow, the sites where the majority of heme is produced. Although the pathophysiologic mechanisms of the clinical manifestations of the porphyrias are not fully understood, two cardinal features prevail: skin photosensitivity and neurologic symptoms of intermittent autonomic neuropathy, acute neurovisceral attacks, and disorders of the nervous system. The primary diagnosis of the proband is based on biochemical testing, which is not always able to identify acute porphyrias, especially in asymptomatic family carriers when heme precursors and porphyrins excretion is normal, low-normal and high-reduced values of enzyme activity overlap, and hematological diseases responsible for abnormal blood cells distribution coexist. Molecular analysis of gene mutations responsible for each type of porphyria is the best diagnostic approach for symptomatic as well as presymptomatic gene carriers (Adv Clin Exp Med 2016, 25, 2, 361-368).

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Co-synthesis of Human δ-Aminolevulinate Dehydratase (ALAD) Mutants with the Wild-type Enzyme in Cell-free System—Critical Importance of Conformation on Enzyme Activity—

Cited by 6 publications

References 27 publications

A framework for application of metabolic modeling in yeast to predict the effects of nsSNV in human orthologs

A framework for application of metabolic modeling in yeast to predict the effects of nsSNV in human orthologs

Heme biosynthesis and the porphyrias

Clinical, Biochemical and Molecular Characteristics of the Main Types of Porphyria

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