Affinity and Rate Constants for Interactions of Bovine Folate-Binding Protein and Folate Derivatives Determined by Optical Biosensor Technology. Effect of Stereoselectivity

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• 作者：Linné ; a Nygren-Babol ; &Aring ; se Sternesjö ; Margareta Jä ; gerstad ; and Lennart Bjö ; rck
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2005
• 出版时间：June 29, 2005
• 年：2005
• 卷：53
• 期：13
• 页码：5473 - 5478
• 全文大小：88K
• 年卷期：v.53,no.13(June 29, 2005)
• ISSN：1520-5118

文摘

The interactions between bovine folate-binding protein (FBP) and different folate derivatives in purediastereoisomeric forms were studied at pH 7.4 by a surface plasmon resonance technology (Biacore).The results show that folic acid had the most rapid association rate (k_a = 1.0 × 10⁶ M^-1 s^-1), whereas(6S)-5-HCO-5,6,7,8-tetrahydrofolic acid had the most rapid dissociation rate (k_d = 3.2 × l0^-3 s^-1).The equilibrium dissociation constant (K_D), calculated from the quotient of k_d/k_a, showed that the twoforms of folates not occurring in nature, that is, folic acid and (6R)-5-CH₃-5,6,7,8-tetrahydrofolic acid,had the highest affinities for FBP, 20 and 160 pmol/L, respectively. The results thus show that therewere great differences in the interactions between folate-binding protein and the major forms of folatederivatives. The nutritional implications of these differences are discussed.Keywords: Folate-binding protein; optical biosensor; rate constant; equilibrium constant; folic acid;5-methyltetrahydrofolate diastereomers