title: Measurement of homocysteine thiolactone hydrolase activity using high-performance liquid chromatography with fluorescence detection and polymorphisms of paraoxonase in normal human serum.
abstract: We developed a non-radioactive and sensitive assay method for measurement of the HTL hydrolase (HTLase) activity in biological samples, using OPA as a fluorescent post-labeling agent, l-homocysteine thiolactone (L-HTL) as the substrate, and HPLC to achieve rapid and selective separation of the substrate and product. The method was applied to measure the activity of HTLase in human, rabbit, rat and mouse serum samples. In addition, the correlation between the serum HTLase activity and PON1 polymorphisms in Japanese subjects was also investigated. The serum HTLase activity in humans, as determined by measurement of the enzyme activity in 22 subjects, was found to be in the range of 0.89-2.06 nmol/min mg protein, with a mean activity of 1.44 nmol/min mg protein.
authors.affiliation: Department of Analytical Biochemistry, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose-Shi, Tokyo 204-8588, Japan. tadayasu@my-pharm.ac.jp
authors.forename: Tadayasu
authors.initials: T
authors.lastname: Togawa
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Mukai
authors.forename: Kazuko
authors.initials: K
authors.lastname: Ohata
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Suzuki
authors.forename: Shinzo
authors.initials: S
authors.lastname: Tanabe
mesh_terms: D000328:Adult; D000818:Animals; D043303:Aryldialkylphosphatase / Q000097:blood* / Q000235:genetics / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005260:Female; D005838:Genotype; D006801:Humans; D007564:Japan; D008297:Male; D051379:Mice; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011817:Rabbits; D051381:Rats; D012016:Reference Values; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence
chemical_list: D043303:Aryldialkylphosphatase; C468406:PON1 protein, human