Structure–activity relationship study of flowering-inducer FN against Lemna paucicostata
摘要:
FN1 (1) and FN2 (2), cycloadducts of alpha-ketol octaclecadienoic acid (3) with norepinephrine (NE), induce flowering in Lemna paucicostata. In order to broaden our understanding of structural requirements of FN for flower induction, nine analogs of 3 (4-12) were synthesized and reacted with NE under basic conditions. These analogs, except for 8, 10, and 12, exhibited significant activity regarding to floral induction in L. paucicostata. Similar experiments were carried out by using 3 and epinephrine, and it was demonstrated that these products also possessed biological activity. (C) 2008 Elsevier Ltd. All rights reserved.
Characterization of hydroxy fatty acid dehydrogenase involved in polyunsaturated fatty acid saturation metabolism in Lactobacillus plantarum AKU 1009a
摘要:
Hydroxy fatty acid dehydrogenase, which is involved in polyunsaturated fatty acid saturation metabolism in Lactobacillus plantarum AKU 1009a, was cloned, expressed, purified, and characterized. The enzyme preferentially catalyzed NADH-dependent hydrogenation of oxo fatty acids over NAD(+)-dependent dehydrogenation of hydroxy fatty acids. In the dehydrogenation reaction, fatty acids with an internal hydroxy group such as 10-hydroxy-cis-12-octadecenoic acid, 12-hydroxy-cis-9-octadecenoic acid, and 13-hydroxy-cis-9-octadecenoic acid served as better substrates than those with alpha- or beta-hydroxy groups such as 3-hydroxyoctadecanoic acid or 2-hydroxyeicosanoic acid. The apparent Km value for 10-hydroxy-cis-12-octadecenoic acid (HYA) was estimated to be 38 mu M with a k(cat) of 7.6 x 10(-3) s(-1). The apparent K-m value for 10-oxo-cis-12-octadecenoic acid (KetoA) was estimated to be 1.8 mu M with a k(cat) of 5.7 x 10(-1) s(-1). In the hydrogenation reaction of KetoA, both (R)- and (S)-HYA were generated, indicating that the enzyme has low stereoselectivity. This is the first report of a dehydrogenase with a preference for fatty acids with an internal hydroxy group. (C) 2015 Elsevier B.V. All rights reserved.