Hirabayashi J
Department of Biological Chemistry, Teikyo University, Kanagawa, Japan.
Q Rev Biol. 1996 Sep;71(3):365-80. doi: 10.1086/419443.
A possible scenario on the origin of elementary hexoses (fructose, glucose, mannose, and galactose) is proposed: (1) Formol reaction, an autocatalytic polymerization reaction, occurred on the primitive earth under weakly alkaline conditions to generate various small molecular compounds. (2) Among them, glyceraldehyde and dihydroxyacetone undergo aldol condensation to produce stable ketohexoses, fructose and sorbose. (3) Subsequently, Lobry de Bruyn rearrangement converts fructose into stable aldohexoses, glucose, and mannose. (4) Thus, prebiotically synthesized ¿first triplet¿ hexoses would have been available for utilization by ancestral primitive microorganisms. (5) After the development of biochemical pathways, various saccharides, including galactose, were biosynthesized from glucose and mannose as ¿bricolage products¿; the utilization of galactose as a key recognition molecule, based on its distinctive axial 4-OH and its outermost location in glycoconjugates, owing to its late arrival, may have evolved concomitantly with the evolution of multicellular organisms.
本文提出了一种关于基本己糖（果糖、葡萄糖、甘露糖和半乳糖）起源的可能情况：（1）在原始地球上，在弱碱性条件下发生了甲醛反应，这是一种自催化聚合反应，生成了各种小分子化合物。（2）其中，甘油醛和二羟基丙酮发生羟醛缩合反应，生成稳定的己酮糖，即果糖和山梨糖。（3）随后，洛布里·德·布吕恩重排反应将果糖转化为稳定的醛己糖，即葡萄糖和甘露糖。（4）因此，益生元合成的“首个三联体”己糖可供原始祖先微生物利用。（5）在生化途径发展之后，包括半乳糖在内的各种糖类作为“拼凑产物”从葡萄糖和甘露糖生物合成；由于半乳糖到达时间较晚，基于其独特的轴向4-羟基及其在糖缀合物中最外层的位置，其作为关键识别分子的利用可能与多细胞生物的进化同时发生。
