Prolidase deficiency is a complex disease characterized by various skin manifestations accompanied by mental retardation, facial dysmorphism and susceptibility to pyogenic infections.
We assessed a patient presenting a peculiar phenotype combining manifestations of prolidase deficiency with features typical of hyper-IgE syndrome. Mutation analysis was performed using direct PCR amplification and PCR restriction fragment length polymorphism analysis.
We identified a novel homozygous recessive mutation in the PEPD gene, which was found to segregate in the family of the patient with the disease and was not found in a panel of DNA samples representative of all major Druze families living in northern Israel.
Our results suggest that prolidase deficiency associated with hyper-IgE syndrome, a rare disorder, can be caused by mutations in PEPD.
[Show abstract][Hide abstract] ABSTRACT: Prolidase is a Mn(2+)-dependent dipeptidase that cleaves imidodipeptides containing C-terminal proline or hydroxyproline. In humans, a lack of prolidase activity causes prolidase deficiency, a rare autosomal recessive disease, characterized by a wide range of clinical outcomes, including severe skin lesions, mental retardation, and infections of the respiratory tract. In this study, recombinant prolidase was produced as a fusion protein with an N-terminal histidine tag in eukaryotic and prokaryotic hosts and purified in a single step using immobilized metal affinity chromatography. The enzyme was characterized in terms of activity against different substrates, in the presence of various bivalent ions, in the presence of the strong inhibitor Cbz-Pro, and at different temperatures and pHs. The recombinant enzyme with and without a tag showed properties mainly indistinguishable from those of the native prolidase from fibroblast lysate. The protein yield was higher from the prokaryotic source, and a detailed long-term stability study of this enzyme at 37 degrees C was therefore undertaken. For this analysis, an 'on-column' digestion of the N-terminal His tag by Factor Xa was performed. A positive effect of Mn(2+) and GSH in the incubation mixture and high stability of the untagged enzyme are reported. Poly(ethylene glycol) and glycerol had a stabilizing effect, the latter being the more effective. In addition, no significant degradation was detected after up to 6 days of incubation with cellular lysate. Generation of the prolidase in Escherichia coli, because of its high yield, stability, and similarity to native prolidase, appears to be the best approach for future structural studies and enzyme replacement therapy.
[Show abstract][Hide abstract] ABSTRACT: Here we summarized what is known at the present about function, structure and effect of mutations in the human prolidase. Among the peptidases, prolidase is the only metalloenzyme that cleaves the iminodipeptides containing a proline or hydroxyproline residue at the C-terminal end. It is relevant in the latest stage of protein catabolism, particularly of those molecules rich in imino acids such as collagens, thus being involved in matrix remodelling. Beside its intracellular functions, prolidase has an antitoxic effect against some organophosphorus molecules, can be used in dietary industry as bitterness reducing agent and recently has been used as target enzyme for specific melanoma prodrug activation. Recombinant human prolidase was produced in prokaryotic and eukaryotic hosts with biochemical properties similar to the endogenous enzyme and represents a valid tool both to better understand the structure and biological function of the enzyme and to develop an enzyme replacement therapy for the prolidase deficiency (PD). Prolidase deficiency is a rare recessive disorder caused by mutations in the prolidase gene and characterized by severe skin lesions. Single amino acid substitutions, exon splicing, deletions and a duplication were described as causative for the disease and are mainly located at highly conserved amino acids in the sequence of prolidase from different species. The pathophysiology of PD is still poorly understood; we offer here a review of the molecular mechanisms so far hypothesized.
[Show abstract][Hide abstract] ABSTRACT: The Druze community is characterized by consanguinity and endogamy, and by reluctance to genetic testing and technological interventions for the prevention of birth defects. Multiple patients with four rare and severe inborn errors of metabolism cerebrotendinous xanthomatosis, prolidase deficiency, argininosuccinate lyase deficiency, and carbamyl phosphate synthetase I deficiency were identified in an isolated Druze village in northern Israel. The aims of this study were to identify couples at risk for four inherited diseases, and to prevent birth defects in a community presenting religious and cultural obstacles to genetic testing.
A genetic screening and counseling program in a high-risk community.
The 1425 residents who attended group genetic counseling sessions between 2003 and 2007 consented to genetic testing. We identified 217 carriers for either one or two disease causing mutations. High carrier frequencies for cerebrotendinous xanthomatosis, prolidase deficiency, argininosuccinate lyase deficiency, and carbamyl phosphate synthetase I deficiency were identified as 1:11, 1:21, 1:41, and 1:95, respectively. Fifty-eight percent (125) of the carriers' spouses agreed to genetic counseling and testing. Ten couples at risk for affected offspring were identified and offered prenatal genetic counseling and diagnosis.
The genetic screening program, the first of its kind reported in a Druze community, was well received. We expect this program to increase awareness of genetic counseling, to contribute to disease prevention, and to serve as a model for other isolated communities.
Genetics in medicine: official journal of the American College of Medical Genetics 01/2009; 10(12):903-9. DOI:10.1097/GIM.0b013e31818d0e0f · 7.33 Impact Factor
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