Pinto E, Catalani L H, Lopes N P, Di Mascio P, Colepicolo P
Departamento de Bioquímica, Universidade de São Paulo, São Paulo, CEP 05599-970, Brazil.
Biochem Biophys Res Commun. 2000 Feb 16;268(2):496-500. doi: 10.1006/bbrc.2000.2142.
Carotenoids in light-harvesting proteins and reaction centers increase the overall efficiency of photosynthesis by transferring absorbed light energy to chlorophylls. Peridinin and beta-carotene were isolated from Gonyaulax polyedra in a one-step purification protocol using the preparative circular chromatography (Chromatotron), performed on silica gel under N(2) atmosphere and n-hexane/acetone 8:2 as mobile phase and characterized by extensive (1)H NMR, infrared, and electrospray ionization mass spectrometry analyses. The quenching of singlet molecular oxygen [O(2) ((1)Delta(g))] was evaluated by NIR-emission assays using singlet oxygen generated by sensitization of either perinaphthenone or methylene blue. The NIR-emission assay showed that peridinin quench as singlet oxygen (k(q) = 9.5 x 10(8) M(-1) s(-1)) 5-fold less efficiently than beta-carotene (52 x 10(8) M(-1) s(-1)). A method, based on the use of high-performance liquid chromatography with UV-VIS detection, was then developed for the sensitive quantification of peridinin (55% of total carotenoids) and beta-carotene (4.1% of total carotenoids). Thus, since peridinin is 10-fold more abundant than beta-carotene, it is expected to be the major protector against the deleterious effects of O(2) ((1)Delta(g)) in Gonyaulax polyedra.
捕光蛋白和反应中心中的类胡萝卜素通过将吸收的光能传递给叶绿素来提高光合作用的整体效率。使用制备型循环色谱法（Chromatotron），在氮气气氛下于硅胶上，以正己烷/丙酮8:2作为流动相，通过一步纯化方案从多边裸甲藻中分离出了多甲藻素和β-胡萝卜素，并通过广泛的¹H NMR、红外和电喷雾电离质谱分析对其进行了表征。使用由苊醌或亚甲蓝敏化产生的单线态氧，通过近红外发射测定法评估单线态分子氧[O₂(¹Δg)]的猝灭情况。近红外发射测定法表明，多甲藻素猝灭单线态氧的效率（k(q)=9.5×10⁸ M⁻¹ s⁻¹）比β-胡萝卜素（52×10⁸ M⁻¹ s⁻¹）低5倍。随后开发了一种基于高效液相色谱-紫外可见检测的方法，用于灵敏定量多甲藻素（占总类胡萝卜素的55%）和β-胡萝卜素（占总类胡萝卜素的4.1%）。因此，由于多甲藻素的含量比β-胡萝卜素高10倍，预计它是多边裸甲藻中抵御O₂(¹Δg)有害影响的主要保护剂。
