title: Kinetics studies on the lignan class of natural compounds that inhibits alpha-chymotrypsin.
abstract: The mechanism of inhibition of the alpha-chymotrypsin enzyme by two lignans of the fused bistetrahydrofuran series, epiexcelsin (1) and 5'-demethoxyepiexcelsin (2), which were isolated from the Commiphora mukul Engl., was investigated. Lineweaver-Burk and Dixon plots and their secondary replots showed that these compounds were noncompetitive inhibitors of the enzyme. K(i) values for 1 and 2 were found to be 22.29 +/- 0.015 and 336.30 +/- 0.053 microM, respectively.
authors.affiliation: Department of Chemistry, Center for Natural Product Drug Development, Government College University, Lahore, Pakistan. atrabbasi@yahoo.com
authors.forename: M A
authors.initials: MA
authors.lastname: Abbasi
authors.forename: M A
authors.initials: MA
authors.lastname: Lodhi
authors.forename: V U
authors.initials: VU
authors.lastname: Ahmad
authors.forename: M I
authors.initials: MI
authors.lastname: Choudhary
mesh_terms: D002918:Chymotrypsin / Q000037:antagonists & inhibitors*; D017705:Lignans / Q000737:chemistry / Q000302:isolation & purification* / Q000493:pharmacokinetics*; D029562:Magnoliaceae / Q000737:chemistry*; D008433:Mathematics; D015394:Molecular Structure; D010154:Pakistan; D010946:Plants, Medicinal / Q000737:chemistry*
chemical_list: C454519:5'-demethoxyepiexcelsin; D017705:Lignans; C547996:epiexcelsin; D002918:Chymotrypsin; C117608:alpha-chymotrypsin