Garcia G E, Wirtz R A, Barr J R, Woolfitt A, Rosenberg R
Departments of Biochemistry and Entomology, Walter Reed Army Institute of Research, Washington, D. C. 20307, USA.
J Biol Chem. 1998 May 15;273(20):12003-5. doi: 10.1074/jbc.273.20.12003.
A small, heat stable chromophore extracted from mosquitoes has recently been implicated as the signal that induces mating of Plasmodium, the malaria parasite. We have used high resolution electrospray mass spectrometry to determine that this gamete activation factor (GAF) has a m/z = 205.0450, suggesting a molecular species composition of C10H7NO4. Xanthurenic acid (XA), a product of tryptophan catabolism, was determined to have an elemental composition, ultraviolet absorbance maxima, and mass spectrum consistent with those characteristics of GAF. XA activated gametogenesis of Plasmodium gallinaceum and P. falciparum in vitro at concentrations lower than 0.5 microM in saline buffered to pH 7.4. A structural analog of XA, kynurenic acid (C10H6NO3), also activated gametogenesis but only at higher concentrations and with less effect. We propose that XA is GAF. This is the first evidence that XA has induction activity.
最近，从蚊子中提取出一种小型、热稳定的发色团，它被认为是诱导疟原虫（疟疾病原体）交配的信号。我们利用高分辨率电喷雾质谱法确定，这种配子激活因子（GAF）的质荷比为m/z = 205.0450，表明其分子组成是C10H7NO4。经测定，色氨酸分解代谢产物黄尿酸（XA）的元素组成、紫外吸收最大值和质谱与GAF的这些特征相符。在pH值为7.4的生理盐水缓冲液中，XA在浓度低于0.5微摩尔时可在体外激活鸡疟原虫和恶性疟原虫的配子发生。XA的结构类似物犬尿酸（C10H6NO3）也能激活配子发生，但仅在较高浓度下起作用，且效果较差。我们认为XA就是GAF。这是黄尿酸具有诱导活性的首个证据。
