Colorimetric Assay for Lecithin Using Two Co-immobilized Enzymes and an Indicator Dye Conjugate

dc.contributor.author	Kotsira, VPh	en
dc.contributor.author	Clonis, YD	en
dc.date.accessioned	2014-06-06T06:43:36Z
dc.date.available	2014-06-06T06:43:36Z
dc.date.issued	1998	en
dc.identifier.issn	00218561	en
dc.identifier.uri	http://62.217.125.90/xmlui/handle/123456789/1387
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-0001742217&partnerID=40&md5=fd8aa486608030a6d3e286ff2221e0a0	en
dc.subject	Bromothymol blue	en
dc.subject	Choline	en
dc.subject	Choline assay	en
dc.subject	Choline oxidase	en
dc.subject	Enzyme assay	en
dc.subject	Immobilized enzymes	en
dc.subject	Lecithin	en
dc.subject	Lecithin assay	en
dc.subject	Optical biosensor	en
dc.subject	Phosphatidylcholine	en
dc.subject	Phospholipase D	en
dc.title	Colorimetric Assay for Lecithin Using Two Co-immobilized Enzymes and an Indicator Dye Conjugate	en
heal.type	journalArticle	en
heal.publicationDate	1998	en
heal.abstract	According to the new assay for lecithin, phospholipase D (PL), choline oxidase (ChOX), and the indicator conjugate bromothymol blue-glutathione (BTB-GSH) are co-immobilized on glutaraldehyde-activated polyacrylamide transparent gel. When a sample containing lecithin is added to the biocatalytic gel, lecithin is hydrolyzed by PL to choline, which is oxidized to betaine by ChOX. The organic acid betaine changes the microenvironmental pH of the enzymes, thus leading the optical absorption of the biocatalytic gel to a hypsochromic shift because of the co-immobilized indicator conjugate, BTB-GSH. The change of the optical absorption at λmax (622 nm) is related linearly to lecithin concentration in the range 20-120 μM. When the optical effect is quantified in a spectrophotometer, the analyte concentration can be determined. The biocatalytic gel is used successfully for lecithin determinations in bovine serum and soybean granules. The principle of the method is applicable to the construction of optical biosensors.	en
heal.journalName	Journal of Agricultural and Food Chemistry	en
dc.identifier.issue	8	en
dc.identifier.volume	46	en
dc.identifier.spage	3389	en
dc.identifier.epage	3394	en