Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.5.1.12 (biotinidase)
392 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Biotinidase was purified from human breast milk (4,000-fold), and was compared with human serum biotinidase (enriched 30,000-fold). The molecular weight of milk enzyme was 68,000 Da as determined by SDS-PAGE. It was definitely smaller than that of serum biotinidase (Mr = 76,000). Isoelectric point of milk biotinidase was 4.6, whereas that of serum biotinidase was 4.3. Sialic acid content in milk biotinidase was less than that found in serum enzyme. N-Acetyl-galactosamine was present in milk enzyme, whereas it was absent in serum enzyme. Milk biotinidase is O-glycosylated, whereas serum biotinidase is N-glycosylated. These differences in glycosylation suggest the existence of different types of excretion mechanisms between milk and serum biotinidase. Both biotinidases were found to be thiol-type enzyme, however, the extent of activation of the enzyme by 2-mercaptoethanol was 13-fold in milk, whilst the serum enzyme was activated only 1.5-fold. Km for biotinyl-4-amino-benzoate was 22 microM in milk enzyme and 50 microM in serum enzyme. Competitive inhibition by biotin (Ki) of milk enzyme was 43 microM and 1.3 mM for serum enzyme. These results suggest the structural differences at or near the active site of the each enzyme.
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PMID:Comparative study on human milk and serum biotinidase. 251 77

An unusual clinical course of a patient with biotinidase deficiency, causing Leigh syndrome, is reported. Laryngeal stridor was the major presenting symptom followed by progressive neurologic deterioration and death at the age of 21.5 mo. Absence of skin and hair abnormalities as well as of organic aciduria delayed the correct diagnosis. Necropsy revealed subacute necrotizing encephalopathy (Leigh syndrome). Carboxylase activities (propionyl CoA carboxylase, 3-methylcrotonyl-CoA carboxylase, pyruvate carboxylase) measured in lymphocytes 1 day before death were decreased to 10% of normal values. Propionyl-CoA carboxylase was shown to be the only stable carboxylase in human postmortem tissue; in our patient it was moderately decreased in postmortem liver (29% of control) and kidney (42%), but severely decreased in brain (3%). These findings might explain the severity of neurological symptoms in the absence of marked organic aciduria. They indicate that in biotinidase deficiency the CNS may become biotin depleted earlier and more severely than other organs. Biotinidase deficiency should be included in the differential diagnosis of Leigh syndrome and of unexplained respiratory problems.
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PMID:Biotinidase deficiency: a cause of subacute necrotizing encephalomyelopathy (Leigh syndrome). Report of a case with lethal outcome. 258 27

At the age of 13 months a patient developed muscular hypotonia, deafness of the inner ear and cutaneous symptoms (alopecia; skin rash, complicated by superinfection with monilia). Biochemical assays revealed compensated metabolic acidosis, pathologically high lactate and pyruvate concentrations in the blood and cerebro-spinal fluid, as well as increased urinary excretion of 3-OH-isovaleric acid, 3-methylcrotonylglycine and lactate. The patient was diagnosed as suffering from autosomal recessive biotinidase deficiency on the basis of severely reduced biotinidase activity in plasma (0.05 nmol/min/ml). In both his parents and brother heterozygosity was found. Institution of therapy with a daily dose of 10 mg biotin rapidly removed most of the symptoms; after six months of treatment the deafness had improved significantly.
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PMID:[Biotinidase deficiency: a congenital metabolic disease which can be successfully treatment with vitamin H]. 260 75

Nutritional approaches are available for the management of several different classes of inborn metabolism errors. In phenylketonuria (PKU), phenylalanine is not properly metabolized; and its accumulation leads to neurologic dysfunction and metal retardation. Altering the diet to limit phenylalanine intake led to remarkable improvement in children with PKU. It was later found that instituting dietary therapy immediately after identification of the disorder in newborns prevented mental retardation. Throughout the 1960s nutritional therapies were found for other inborn disorders, including galactosemia, maple syrup urine disease, and homocystinuria. For the group of disorders associated with defects in the urea cycle, leading to profound hyperammonemia, therapy based on the concept of waste nitrogen excretion (i.e., by increasing excretion of urea cycle intermediates in the urine, nitrogen that would otherwise recycle as ammonia can be eliminated) dramatically produced better control of hyperammonemia and its consequences. Some inborn errors of metabolism respond to vitamin therapy. Biotin-related multiple carboxylase synthetase deficiency can be produced by either of two enzyme defects--holocarboxylase synthetase deficiency or biotinidase deficiency. Both are treatable with biotin supplementation. The symptoms of multiple carboxylase deficiency can also occur after intestinal resection or ingestion of raw eggs. Multiple carboxylase deficiency has been treated successfully in utero by giving the mother biotin supplements. Peroxisomal disorders may respond to dietary management. Liver disease in hereditary tyrosinemia may be accentuated by hypermethioninemia and treated by controlling the blood methionine level. Glycogen storage disease Type I, which causes hypoglycemia, can be controlled by oral administration of cornstarch.
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PMID:Nutritional therapy for selected inborn errors of metabolism. 268 28

In this automated procedure for quantifying biotinidase activity in human serum, a manual colorimetric method that measures conversion of the enzyme's artificial substrate N-biotinyl p-aminobenzoate was modified for use with a Technicon AutoAnalyzer II. The intra-run replicate precision (CV) was 2.1% and the day-to-day CV was 4.6% for quality-control sera. Results were linearly related to biotinidase activity in serum over the complete range of clinically relevant values, 0.2 to 11.0 U/L. Moreover, results of the automated assay were not significantly different from those of the manual assay. Because the automated procedure is faster and more precise, we recommend it for population-based studies and some screening studies.
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PMID:An automated procedure for measuring biotinidase activity in serum. 272 Sep 79

Guinea pig biotinidase and lipoamidase were mostly located in the liver microsomal fraction. Approx. 80% of the total activities of both enzymes were associated with the membranes subfractions of liver. The subunit molecular masses of these enzymes as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of microsomal biotinidase and lipoamidase were 70 and 60 kDa, respectively. Sephadex G-200 gel-permeation chromatography in the presence of 0.1% Nonidet P-40 indicated that the native-state molecular masses of microsomal biotinidase and lipoamidase were 68 and 120 kDa, respectively. The isoelectric points of microsomal biotinidase and lipoamidase were 6.3 and 5.7, respectively. Linear sucrose density centrifugation analysis indicated that both enzymes exist in the rough endoplasmic reticulum. Comparison of amino acid analyses indicated a higher content of leucine and lower content of serine in lipoamidase than in biotinidase. Microsomal biotinidase and lipoamidase were classified as being thiol-type and serine-type amidases, respectively.
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PMID:Biotinidase and lipoamidase in guinea pig livers. 273 Sep 18

A simple and rapid method for the quantitation of biotinidase activity in blood-soaked filter paper spots was developed. The assay measures the release of p-aminobenzoate from N-biotinyl-p-aminobenzoate. A microtiter transfer plate is used to rapidly separate the reaction solution from the filter paper spots. Color is developed and the absorbance is determined using a microplate reader. The biotinidase activity in frozen filter spots correlates well with the activity in serum (r = 0.94). The enzyme activities of obligate heterozygotes for biotinidase deficiency were significantly different from those with normal activity (P = 0.03). This rapid screening procedure can be used to quantitate biotinidase activity in newborn screening samples, identify heterozygotes, and estimate the gene frequency and incidence of biotinidase deficiency in large populations. In addition, the use of microtiter transfer plates can be applied to other assays in which the separation of the incubation solution from a filter paper spot is required.
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PMID:The quantitation of biotinidase activity in dried blood spots using microtiter transfer plates: identification of biotinidase-deficient and heterozygous individuals. 277 84

A case of an infant suffering from progressive lethargy, sparse scalp hair, autistic-like behavior, myoclonias, and drug-resistant generalized seizures is reported. Laboratory investigations revealed, in the absence of metabolic acidosis, an increased urinary excretion of 2-ketoglutaric acid and a small peak of 3-hydroxyisovaleric acid. The serum biotinidase activity was 0.15 nmol min-1 ml-1 (normal range 5.2 +/- 0.9) in the propositus and 0.310 and 0.420 in her father and mother, respectively. The interictal EEG showed multifocal abnormalities; numerous seizures were recorded, with the pattern of true tonic-clonic fits, exceptional in infancy. Also myoclonias, auditory myoclonus, and repetitive startles were documented. Because of dramatic improvement of all symptoms and signs after starting biotin (5 mg twice daily), the authors suggest a therapeutical trial in all drug-resistant infantile seizures.
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PMID:Biotin-responsive infantile encephalopathy: EEG-polygraphic study of a case. 279 32

There appear to be at least two underlying aetiologies for combined carboxylase deficiency; firstly, a failure of biotinylation of apocarboxylases due to a mutation of holocarboxylase synthetase (EC 6.3.4.10) which results in an enzyme with a high Km with respect to biotin and secondly, a failure of biotinylation due to a lowered availability of biotin due to biotinidase deficiency (EC 3.5.1.12). In both these disorders secondary defects of all four biotin-dependent carboxylases result which in turn causes the excretion of the metabolites characteristic of the isolated carboxylase deficiencies. In addition, both disorders respond biochemically and clinically to the administration of large amounts of biotin.
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PMID:Enzyme studies in biotin-responsive disorders. 286 73

An assay for biotinidase using biocytin, the natural substrate, is described. The fluorometric procedure uses 1,2-diacetylbenzene which reacts selectively with lysine allowing its direct determination in mixture with biocytin. We have examined the applicability of the assay using human serum biotinidase.
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PMID:A fluorometric assay for biotinidase. 308 43


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