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Biomedical subjects

T Murachi

Publications and source records attributed to T Murachi.

195 records · Page 11Linked to original sources
PubMedDate not supplied

A chemiluminometric method for the determination of urea in serum using a three-enzyme bioreactor.

A flow injection chemiluminometric assay for urea has been developed based on a minicolumn bioreactor packed with immobilized enzyme-bearing glass beads. The reactor contains immobilized urease, L-glutamate dehydrogenase and L-glutamate oxidase, aligned in this order (upstream to the downstream). When the sample is introduced into the bioreactor, urea is first hydrolysed by urease to produce ammonia, which is then converted into L-glutamate by L-glutamate dehydrogenase. L-Glutamate is finally oxidized by L-glutamate oxidase to produce hydrogen peroxide, which is quantified by measuring chemiluminescence emitted upon admixing with luminol and potassium ferricyanide. One assay cycle is completed within 1 minute. The method is sensitive (detection limit 0.5 nmol) and is linear in the range 0-30 mmol/l. It can be readily applied to the determination of urea in human serum, and requires no blank corrections for ammonia and/or L-glutamate present in serum samples.

Amino Acid Oxidoreductases↗
PubMedDate not supplied

Specific enzymatic assay method for homocysteine and its application to the screening of neonatal homocystinuria.

A simple and specific enzymatic assay method for homocysteine is described. The method is based on the formation of S-adenosylhomocysteine from adenosine and homocysteine through the catalysis of S-adenosylhomocysteine hydrolase (EC 3.3.1.1), followed by its separation by high-performance liquid chromatography. The results for human blood, serum, and urine and those extracted from filter paper showed good correlation with those obtained on measurement with a conventional amino acid analyzer, which demonstrates that the method is useful for neonatal screening for homocystinuria.

Adenosylhomocysteinase↗