An Ultraviolet Spectrophotometric Assay for Measuring Lipase Activity Using Long-Chain Triacyglycerols from Aleurites fordii Seeds

An ultraviolet spectrophotometric assay for the screening of sn-2-specific lipases using 1,3-O-dioleoyl-2-O-α-eleostearoyl-sn-glycerol as substrate

“…Interestingly, the maxima of the spectra obtained herein for sn -OEO (respectively, TAGs in tung oil) undergo a reproducible 2 nm (respectively, 1 nm) blue shift. This correlates with the positive solvatochromism observed earlier ( 21 ) and with a reduction in the polarity surrounding the ␣ -eleostearic acid moiety while shifting from ethanol to the sn -1/3 position in tung oil and to the sn -2 position in between two oleic side chains in sn -OEO ( 40 )…”

“…3 ). The profi le of the spectrum appeared to be similar (240-300 nm), displaying three typical peaks around 260, 270, and 280 nm ( 21 ). Still, a slight solvochromic effect, which was pointed out earlier ( 40 ), could be observed in the ␣ -eleostearic acid-containing products and provided some information about the local polarity surrounding the trienic FA moiety.…”

“…Petry et al ( 20 ) developed a continuous, sensitive in vitro lipase assay using a MAG containing a fl uorescent label, p -nitrobenzofurazan, as lipase substrate. An alternative ultraviolet (UV) spectrophotometric assay based on the use of TAG from Aleurites fordii seeds that is less sensitive to oxidation was introduced by our group ( 21 ). A. fordii is a tree originating from China, where its seed oil, known as tung oil, is one of the main primary products used in the lacquer industry.…”

“…Crude tung oil contains up to 70% ␣ -eleostearic acid ( 22,23 ), an octadecatrienoic FA with a conjugated triene containing double bonds having ⌬ ( 23 ) showed that ␣ -eleostearic acid is esterifi ed at the sn-1 and sn-3 positions in the TAGs present in tung oil. The conjugated triene present in ␣ -eleostearic acid is an intrinsic chromophore that confers strong UV absorption properties on both the pure FA ( 24 ) and the TAGs present in tung oil ( 21 ). More recently, the UV spectrophotometric lipase assay with tung oil was adapted to microtiter plates for high-throughput screening procedures ( 25 ).…”

Sensitive assay for hormone-sensitive lipase using NBD-labeled monoacylglycerol to detect low activities in rat adipocytes

“…But its pronounced sensitivity to oxidation precludes its use under routine conditions (S. Petry, H. Jordan, H. Kleine, and N. Tennagels, unpublished results). An alternative ultraviolet spectrophotometric assay based on the use of TAG from Aleutris fordii seeds, which is less sensitive to oxidation, was recently introduced by our group (12).…”