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F Endo

Publications and source records attributed to F Endo.

At least 127 records · Page 7Linked to original sources
PubMed1991

Molecular basis of prolidase (peptidase D) deficiency.

Human prolidase (PEPD, iminodipeptidase, EC 3.4.13.9) and related deficiencies were analyzed in terms of the nature and molecular biology of the enzyme and the molecular events seen in patients with this deficiency. The analyses were based on findings concerning isolation of the enzyme, development of specific antibodies and molecular cloning of cDNA and genome DNA of human prolidase. The studies revealed that human prolidase is a homo-dimer of an identical subunit 492 amino acid residues. The gene for prolidase (PEPD gene) was localized on chromosome 19, spanned more than 130 x 10(3) base-pairs and split into 15 exons. Molecular defects in prolidase deficiency were then analyzed. Two patients with the polypeptide-positive phenotype of the disease carried a mis-sense mutation of exon 12. Two siblings with a polypeptide-negative phenotype carried a gene deletion that encompassed exon 14. These mutations were not found in ten other patients with the disease, hence the molecular defects in prolidase deficiency are apparently highly heterogeneous.

Base Sequence↗
PubMed1991

A murine model for type III tyrosinemia: lack of immunologically detectable 4-hydroxyphenylpyruvic acid dioxygenase enzyme protein in a novel mouse strain with hypertyrosinemia.

We have characterized a new mutant strain of mouse that has hypertyrosinemia. The blood tyrosine level was persistently high, and increased amounts of 4-hydroxyphenylpyruvic acid and its derivatives were excreted into the urine. Succinylacetone was not detected in urine samples from these mice. All the animals were apparently healthy, and there was no evidence of hepatorenal dysfunction. The hypertyrosinemia was transmitted through an autosomal recessive inheritance. Analyses of hepatic enzymes related to tyrosine metabolism revealed that 4-hydroxyphenylpyruvic acid dioxygenase activity was virtually absent, while fumarylacetoacetase and tyrosine aminotransferases (cytosolic and mitochondrial forms) were normal in these mutant mice. Immunoblot analysis of 4-hydroxyphenylpyruvic acid dioxygenase protein in the liver indicated that the subunit protein of the enzyme was absent. It would appear that hypertyrosinemia in this mutant strain was caused by a genetic defect in 4-hydroxyphenylpyruvic acid dioxygenase. These features are similar to type III tyrosinemia in humans. Analysis of this mutant strain of mouse is expected to provide valuable information on the pathogenesis of human type III tyrosinemia and can also serve as a useful system for studies on tyrosine metabolism.

4-Hydroxyphenylpyruvate Dioxygenase↗
PubMed1990

A T-to-A substitution in the E1 alpha subunit gene of the branched-chain alpha-ketoacid dehydrogenase complex in two cell lines derived from Menonite maple syrup urine disease patients.

We cloned and sequenced cDNAs of the E1 alpha and E1 beta subunits of the branched chain alpha-ketoacid dehydrogenase complex (BCKDH) in two cell lines derived from two different Menonite MSUD patients (GM 1655, GM 1099). A T-to-A substitution which generates an asparagine in place of a tyrosine at amino acid 394 of the mature E1 alpha subunit was present in both alleles in these two cell lines, whereas cDNAs of the E1 beta subunit in these cell lines were identical to that of normal human lymphoid cell line and that of the clone from a human placenta cDNA library. It is suggested that the Menonite MSUD is caused by the missense mutation of the E1 alpha subunit of the BCKDH complex.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1990

Structural organization of the gene for human prolidase (peptidase D) and demonstration of a partial gene deletion in a patient with prolidase deficiency.

Prolidase (peptidase D) catalyzes hydrolysis of the di- and tripeptide with carboxyl-terminal proline and plays an important role in recycling proline in various cells and tissues. By using human prolidase cDNA as a probe, a chromosomal gene related to prolidase was isolated from human gene libraries. The human prolidase gene is over 130 kilobases long and is split into 15 exons. All of the splice donor and acceptor sites conform to the GT/AG rule. The transcription initiation site was determined by nuclease S1 mapping and primer extension and was located 131 bases upstream from the initiation codon. A "CAAT" box-like sequence was present 67 bases upstream from the cap site, but there was no "TATA" box-like sequence. There were seven sets of sequences resembling the transcription factor Sp1 binding sites. Four were upstream from the cap site, and three were downstream. We also analyzed findings in patients with prolidase deficiency with respect to major gene re-arrangement. Several hundred base deletions, including the 14th exon, were identified. Knowledge of the gene structure of human prolidase will facilitate further studies on the expression and regulation of this gene and provide necessary information for analyses of mutations in patients with this deficiency.

Base Sequence↗
PubMed1990

Isolation and characterization of a complementary DNA clone coding for the E1 beta subunit of the bovine branched-chain alpha-ketoacid dehydrogenase complex: complete amino acid sequence of the precursor protein and its proteolytic processing.

A 1.7-kb cDNA clone encoding the entire precursor of the E1 beta subunit of the branched-chain alpha-ketoacid dehydrogenase (BCKDH) complex was isolated from a bovine liver cDNA library by screening with a mixture of synthetic oligonucleotide probes corresponding to the C-terminal five-residue sequence of the mature E1 beta subunit. A partial amino acid sequence was determined by Edman degradation of the intact subunit and the peptides generated by cleavage at the lysyl bonds. Nucleotide sequence analysis revealed that the isolated cDNA clone contained the 5'-untranslated sequence of 186 nucleotides, the translated sequence of 1176 nucleotides, and the 3'-untranslated sequence of 306 nucleotides with a poly(A) tail. A type AATAAA polyadenylation signal was located 17 nucleotides upstream of the start of a poly(A) tail. Comparison of the amino acid sequence predicted from the nucleotide sequence of the cDNA insert of the clone with the partial amino acid sequence of the mature BCKDH E1 beta subunit showed that the cDNA insert encodes for a 342 amino acid subunit with Mr 37,745 and that the subunit is synthesized as the precursor with a leader sequence of 50 amino acids and processed at the N-terminus. Northern blot analysis using the cDNA insert as a probe showed the presence of a 1.8-1.9-kb mRNA in bovine liver, suggesting that the insert covers nearly a full length of mRNA. Alignment of the deduced amino acid sequence of bovine BCKDH E1 beta with that of the human pyruvate dehydrogenase (PDH) complex E1 beta subunit revealed a high degree of sequence homology throughout the two enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1990

Carnitine status and blood ammonium levels in low birth weight infants.

Forty-three low birth weight infants appropriate for gestational age (AGA) were monitored to evaluate carnitine status in relation to blood ammonium levels. The infants were grouped into three depending on blood ammonium level on postnatal day 7: 62.9 +/- 3.8 mumol/L in group 1 (N = 13), 38.9 +/- 8.4 mumol/L in group 2 (N = 23), and 24.5 +/- 2.9 mumol/L in group 3 (N = 9). Plasma free carnitine levels decreased in all three groups (p less than 0.001) and plasma short chain acylcarnitine increased only in group 1 (p less than 0.002), compared to findings in normal infants. The blood ammonium level positively and negatively correlated to plasma short chain acylcarnitine (p less than 0.002) and plasma free carnitine levels (p less than 0.002), respectively. The reabsorption rate of free carnitine in renal tubules (RRFC) was decreased at rates of 37.5, 27.5, and 25% of infants in groups 1, 2, and 3, respectively. The acylcarnitine/free carnitine clearance ratio (RAFCC) was decreased in groups 1 (p less than 0.01) and 2 (p less than 0.05) compared with group 3. Thus, an accumulation of short chain acyl moieties and insufficiency in renal absorption of free carnitine are putative causes of lowered plasma free carnitine in infants with higher blood levels of ammonium. The possibility that the carnitine status regulates blood ammonium levels in low birth weight infants warrants continued investigation.

Ammonia↗
PubMed1990

Oral supplementation of vitamin K for pregnant women and effects on levels of plasma vitamin K and PIVKA-II in the neonate.

Levels of plasma vitamin K1 (VK1) and vitamin K2 (VK2) and protein-induced vitamin K absence-II (PIVKA-II) were measured in Japanese mothers and their newborn (N = 33). Twenty milligrams of VK1 (N = 11) or VK2 (N = 12) were given orally to randomly selected mothers 7 to 10 days prior to delivery. Means of plasma VK1 and VK2 concentrations were significantly higher in VK1 (p less than 0.01) and VK2 (p less than 0.01) treated mothers than in the controls at delivery, respectively. Similarly, these levels were significantly elevated in cord plasma in VK1 (p less than 0.05) and VK2 (p less than 0.05) treated groups, compared with findings in the control group, although there was a large concentration gradient between maternal and cord plasma (mostly less than one-tenth). A significant positive correlation was found in VK1 concentration between maternal and cord plasma (N = 33, p less than 0.01), and the proportion of PIVKA-II-positive infants was significantly lower in the VK treated groups than in the control group at birth (p less than 0.05). On the fifth postnatal day, mean levels of VK1 (p less than 0.01) and VK2 (p less than 0.01) in breast milk were significantly higher in the VK1 and VK2 treated mothers than in the control mothers, respectively. In the control group, 9 of 10 infants had a positive PIVKA-II, but no one in the treated groups was positive, thereby indicating significant differences between control and treated groups (p less than 0.01 and p less than 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1990

Biochemical basis of prolidase deficiency. Polypeptide and RNA phenotypes and the relation to clinical phenotypes.

Cultured skin fibroblasts or lymphoblastoid cells from eight patients with clinical symptoms of prolidase deficiency were analyzed in terms of enzyme activity, presence of material crossreacting with specific antibodies, biosynthesis of the polypeptide, and mRNA corresponding to the enzyme. There are at least two enzymes that hydrolyze imidodipeptides in these cells and these two enzymes could be separated by an immunochemical procedure. The specific assay for prolidase showed that the enzyme activity was virtually absent in six cell strains and was markedly reduced in two (less than 3% of controls). The activities of the labile enzyme that did not immunoprecipitate with the anti-prolidase antibody were decreased in the cells (30-60% of controls). Cell strains with residual activities of prolidase had immunological polypeptides crossreacting with a Mr 56,000, similar to findings in the normal enzyme. The polypeptide biosynthesis in these cells and the controls was similar. Northern blot analyses revealed the presence of mRNA in the polypeptide-positive cells, yet it was absent in the polypeptide-negative cells. The substrate specificities analyzed in the partially purified enzymes from the polypeptide-positive cell strains differed, presumably due to different mutations. Thus, there seems to be a molecular heterogeneity in prolidase deficiency. There was no apparent relation between the clinical symptoms and the biochemical phenotypes, except that mental retardation was present in the polypeptide-negative patients. The activities of the labile enzyme may not be a major factor in modifying the clinical symptoms.

Adolescent↗
PubMed1990

Maple syrup urine disease. Complete primary structure of the E1 beta subunit of human branched chain alpha-ketoacid dehydrogenase complex deduced from the nucleotide sequence and a gene analysis of patients with this disease.

A defect in the E1 beta subunit of the branched chain alpha-ketoacid dehydrogenase (BCKDH) complex is one cause of maple syrup urine disease (MSUD). In an attempt to elucidate the molecular basis of MSUD, we isolated and characterized a 1.35 kbp cDNA clone encoding the entire precursor of the E1 beta subunit of BCKDH complex from a human placental cDNA library. Nucleotide sequence analysis revealed that the isolated cDNA clone (lambda hBE1 beta-1) contained a 5'-untranslated sequence of four nucleotides, the translated sequence of 1,176 nucleotides and the 3'-untranslated sequence of 169 nucleotides. Comparison of the amino acid sequence predicted from the nucleotide sequence of the cDNA insert of the clone with the NH2-terminal amino acid sequence of the purified mature bovine BCKDH-E1 beta subunit showed that the cDNA insert encodes for a 342-amino acid subunit with a Mr = 37,585. The subunit is synthesized as the precursor with a leader sequence of 50 amino acids and is processed at the NH2 terminus. A search for protein homology revealed that the primary structure of human BCKDH-E1 beta was similar to the bovine BCKDH-E1 beta and to the E1 beta subunit of human pyruvate dehydrogenase complex, in all regions. The structures and functions of mammalian alpha-ketoacid dehydrogenase complexes are apparently highly conserved. Genomic DNA from lymphoblastoid cell lines derived from normal and five MSUD patients, in whom E1 beta was not detected by immunoblot analysis, gave the same restriction maps on Southern blot analysis. The gene has at least 80 kbp.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1990

A single nucleotide change in the prolidase gene in fibroblasts from two patients with polypeptide positive prolidase deficiency. Expression of the mutant enzyme in NIH 3T3 cells.

Prolidase deficiency is an autosomal recessive disorder characterized by mental retardation and various skin lesions. Cultured skin fibroblasts were obtained from two independent patients with abnormal prolidase. Using the polymerase chain reaction, we amplified the entire coding region of human prolidase mRNA derived from patients' fibroblasts. Nucleotide sequence analysis of amplified cDNA products revealed a G to A substitution at position 826 in exon 12, where aspartic acid was replaced by asparagine at the amino acid residue 276, in cells from both patients. An analysis of the DNA showed that the substitution was homozygous. An expression plasmid clone containing a normal human prolidase cDNA (pEPD-W) or mutant prolidase cDNA (pEPD-M) was prepared, transfected, and tested for expression in NIH 3T3 cells. Incorporation of pEPD-W and pEPD-M resulted in the synthesis of an immunological polypeptide that corresponded to human prolidase. Active human enzyme was detected in cells transfected with pEPD-W, but not in those transfected with pEPD-M. These results were compatible with our observation of fibroblasts and confirmed that the substitution was responsible for the enzyme deficiency. As active prolidase was recovered in prolidase-deficient fibroblasts transfected with pEPD-W, this restoration of prolidase activity after transfection means that gene replacement therapy for individuals with this human disorder can be given due consideration.

Animals↗
PubMed1989

Complete primary structure of the transacylase (E2b) subunit of the human branched chain alpha-keto acid dehydrogenase complex.

We isolated from a placental cDNA library by immunoscreening a cDNA clone encoding the transacylase (E2b) precursor of the human branched chain alpha-keto acid dehydrogenase (BCKDH) complex. The cDNA insert consists of 2,649 base pairs with an open reading frame of 1,431 base pairs which can be translated into 477 amino acids and a 3'-untranslated region of 1,205 base pairs. The deduced amino acid sequence includes a leader peptide of 56 amino acid residues, a lipoyl-bearing domain, a E3-binding domain and an inner core domain. A mature human E2b subunit is likely to contain 421 amino acid residues with a calculated Mr 46,322. The nucleotide sequence of the open reading frame and the deduced amino acid sequence of the human E2b shows 91.6% and 92.0% homology with those of the bovine E2b subunit, respectively.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1989

Primary structure and gene localization of human prolidase.

Complementary DNA clones of prolidase (imidodipeptidase, EC 3.4.13.9) were isolated from human liver and placental cDNA libraries. Two clones named lambda PL21 and lambda PP6 from the liver and placental cDNA libraries, respectively, were analyzed in detail. The first clone, lambda PL21, carried a cDNA insert of 1.7 kilobase pairs and covered all the coding region of human prolidase mRNA. The second clone, lambda PP6, contained a 1.8-kilobase insert with a full-length 3'-untranslated region. Comparison of the amino acid sequence predicted from the nucleotide sequence of the cDNA insert of the two clones with the partial amino acid sequence determined by Edman degradation of peptides derived from human erythrocyte prolidase established that both clones code for human prolidase. The amino terminus of the human mature enzyme is blocked and seems to begin with the sequence X-Ala-Ala-Ala. Presumably no processing occurs at the carboxyl terminus. The mature enzyme is composed of 492 residues, corresponding to Mr 54,305. The sequence of prolidase is unique and not similar to any known protein, except for a significant similarity to regions of F1-ATPase alpha and beta subunits from various sources. The gene has been mapped to the short arm of chromosome 19 (19p13.2). Elucidation of the complete amino acid sequence and the gene location of prolidase should provide the basis for understanding structure-function relationships and also inherited disorders caused by deficiency of this metabolically important enzyme.

Amino Acid Sequence↗