An ultraviolet spectrophotometric assay for α-naphthyl acetate and α-naphthyl butyrate esterases

✍ Scribed by Walter Mastropaolo; Joseph Yourno

• Book ID: 102626545
• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 426 KB
• Volume: 115
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(81)90544-3

✦ Synopsis

A direct, continuous spectrophotometric assay for a-naphthyl acetate esterase and a-naph-thy1 butyrate esterase from human leukocytes has been developed. The method is based on an increase in absorbance at 235 nm which occurs with the hydrolysis of a-naphthyl esters to a-naphthol. This reaction is linear for at least 10 min at 37°C. and esterase activity is proportional to sample size up to at least 80 rg of protein or 5 mU of enzyme, with human mononuclear leukocyte preparations as an esterase source. The saturating concentration is 0.15 mM for both substrates. The effects of pH and NaCl concentration on the assay were also evaluated. This assay has advantages of speed, simplicity, and sensitivity.