• Korean Journal of Food Science and Technology
• /
• v.39 no.1
• /
• pp.94-98
• /
• 2007

Ethyl carbamate, which is also known as a possible human carcinogen, is formed by ethanolysis of N-carbamyl compounds such as carbamyl phosphate, urea, or citrulline. NaCl that is highly present in fermented foods was suspected to have an influence on ethyl carbamate formation. This study was designed to determine the effect of NaCl on the chemical reactions upon incubation of ethanol with the N-carbamyl compound in a 25% NaCl solution or in the absence of NaCl, and to find a possible association with the formation of ethyl carbamate. While the amount of ethyl carbamate formed in a urea solution with the addition of NaCl was increased up to 26%, the amount formed with citrulline or carbamyl phosphate in the presence of NaCl was decreased up to 30% and 40%, respectively. This indicates that NaCl should be considered as a potential factor influencing the rate of ethyl carbamate formation from its precursors.

• BMB Reports
• /
• v.38 no.1
• /
• pp.28-33
• /
• 2005

A gene coding a novel isoform of carbamyl phosphate synthetase I (CPS1) was cloned from a human testicular library. As shown by cDNA microarray hybridization, this gene was expressed at a higher level in human adult testes than in fetal testes. The full length of its cDNA was 3831 bp, with a 3149 bp open reading frame, encoding a 1050-amino-acid protein. The cDNA sequence was deposited in the GenBank (AY317138). Sequence analysis showed that it was homologous to the human CPS1 gene. The putative protein contained functional domains composing the intact large subunit of carbamoyl phosphate synthetase, thus indicated it has the capability of arginine biosynthesis. A multiple tissue expression profile showed high expression of this gene in human testis, suggesting the novel alternative splicing form of CPS1 may be correlated with human spermatogenesis.

• Journal of Genetic Medicine
• /
• v.1 no.1
• /
• pp.5-10
• /
• 1997

The amino acids formed by degradation of proteins ingested produce ammonia. The ammonia which is broken down and excreted as urea through a process known as the Klebs-Hensleit cycle or the urea cycle (Rezvani, 1995). The urea cycle consists of five enzymes necessary for the synthesis of carbamyl phosphate, citrulline, argininosuccinate, arginine, and urea: carbamyl phosphate synthetase (CPS), ornithine transcarbamylase (OTC), argininosuccinate synthetase (AS), argininosuccinate lyase (AL), and arginase (ARG) (Lloyd, 1992). Congenital deficiencies of the enzymes involved in the urea cycle are diseases that are almost fatal without treatment, showing symptoms like vomiting, lethargy, dyspnea, and coma due to hyperammonemia coming from the accumulation of ammonia and metabolic precursors resulting from the deficiency of one of these enzymes (Batshaw and Brusilow, 1983). Among these, the disease manifested by the congenital deficiency of argininosuccinate synthetase (AS) which is associated with the formation of argininosuccinate in citrulline is called argininosuccinate synthetase deficiency or citrullinemia. There have been two reports on this so far in Korea; one in July 1987 by Kim et al. and the other by Park et al. in 1995. We are to report a case of successful treatment of a child with citrullinemia who was transferred to our hospital due to dyspnea, lethargy, feeding difficulties, convulsions and cyanosis together with some document studies related to this case.

• Journal of Yeungnam Medical Science
• /
• v.24 no.2
• /
• pp.322-328
• /
• 2007

Ornithine transcarbamylase (OTC) deficiency is the most common inborn error of urea cycle metabolism; it is inherited in an X-linked manner. The OTC catalyzes the third step of the urea cycle, the conversion of ornithine and carbamyl phosphate to citrulline. Deficiency of OTC leads to the accumulation of ammonia, causing neurological deficits. In most affected hemizygote males, OTC deficiency manifests as hyperammonemic coma that often leads to death in the newborn period, and those who recover from the coma may be neurologically impaired due to the sequelae of the hyperammonemic encephalopathy. In some, late-onset manifestations develop. We report a male neonate with early onset OT deficiency that had apnea and was comatous. On mutation analysis using DNA sequencing after polymerase chain reaction (PCR) amplification of the 10 exons, deletions of 10 bases in codon 285, causing a frame shift was detected in exon 8. The mother and a sister were diagnosed as female carriers. Therefore, genetic counseling and the risk assessment could be provided to the family.

• Applied Biological Chemistry
• /
• v.38 no.2
• /
• pp.118-122
• /
• 1995

Escherichia Coli ornithine transcarbamylase is the enzyme which catalyzes the L-citrulline biosynthesis from L-ornithine and carbamyl phosphate. To facilitate the purification of enzyme which will be used for many biochemical studies such as structure and function relationships and catalytic mechanisms, the cloning and expression of E. coli argI gene for ornithine transcarbamylase was conducted. argI was amplified from genomic DNA of E. coli strain of $DH5{\alpha}$, by polymerization chain reaction (PCR) method. The amplified argI gene was ligated to the prokaryotic expression vector pKK223-3 and used for transformation of E. coli TB2 which was deficient of ornithine transcarbamylase. The over-produced enzyme by the tnansformant was purified by ammonium sulfate fractionation, heat denaturation and affinity chromatography. The result of SDS denaturation gel electrophoresis for the purified enzyme showed a single band of about 38 kDa of ornithine transcarbamylase. Kinetic data for the expressed enzyme gave almost the s?????? values as those of the wild type enzyme. The $k_{cat}$, of the enzyme was $1.0{\times}10^5min^{-1}$, and $K_ms$ for ornithine and carbamyl phosphate were 0.35 mM and 0.06 mM, respectively.

• Journal of The Korean Society of Inherited Metabolic disease
• /
• v.5 no.1
• /
• pp.76-87
• /
• 2005

Various disorders cause hyperammonemia during childhood. Amongthem are those caused by inherited defects in urea synthesis and related metabolic pathways. These disorders can be grouped into two types: disorders of the enzymes that comprise the urea cycle, and disorders of the transporters or metabolites of theamino acids related to the urea cycle. Principal clinical features of these disorders are caused by elevated levels of blood ammonium. Additional disease-specific symptoms are related to the particular metabolic defect. These specific clinical manifestations are often due to an excess or lack of specific amino acids. Treatment of urea cycle disorders and related metabolic diseases consists of nutritional restriction of proteins, administration of specific amino acids, and use of alternative pathways for discarding excess nitrogen. Although combinations of these treatments are extensively employed, the prognosis of severe cases remains unsatisfactory. Liver transplantation is one alternative for which a better prognosis is reported.