Abstract:

Spermidine （Spd） is a type of trimethylamine metabolite widely present in living organisms. However， the abundance of Spd in natural biological systems is extremely low and traditional chemical synthesis methods are cumbersome and environmentally burden some， making it difficult for existing production mode to meet the increasing market demand. This review systematically summarized the biosynthesis mechanism of spermidine， with a focus on analyzing three pathways of spermidine synthesis， including the classical spermidine synthase spermidine synthase （SPDS） pathway， the synthesis pathway based on carboxyaminopropylagmatine （CAPA）， and the pathway based on L-aspartate-4-semialdehyde （L-Asa）. The differences in key pathway enzymes， the distribution of precursor substance metabolic flow， and the efficiency of transmembrane transport were explored， and the research progress of metabolic engineering and enzyme engineering strategies in optimizing the spermidine pathway was summarized. The bottleneck problems existing in the current spermidine biosynthesis system were analyzed， aiming to provide theoretical support and technical references for constructing high-yield cell factories and promoting the industrialized biological manufacturing of spermidine.

Key words: biosynthesis, spermidine, metabolic pathway analysis

摘要：

亚精胺（spermidine，Spd）是一种广泛存在于生物体内的三胺类代谢物，然而天然生物体内亚精胺丰度极低，传统化学合成法步骤繁琐且环境负担较大，导致现有生产模式难以满足日益增长的市场需求。系统综述了亚精胺的生物合成机制，重点解析了三条亚精胺合成途径，包括经典的精胺合酶（spermidine synthase，SPDS)途径、基于羧氨丙基胍（carboxyaminopropylagmatine，CAPA）的合成途径及基于天冬氨酸半醛（L-aspartate-4-semialdehyde，L-Asa）途径，并对其中关键途径酶的差异、前体物质代谢流分配和跨膜转运效率等进行了探讨，总结了代谢工程与酶工程策略在亚精胺途径优化中的研究进展，剖析了当前亚精胺生物合成体系存在的瓶颈问题，旨在为构建高产细胞工厂和推动亚精胺工业化生物制造提供理论支撑与技术参考。

关键词: 生物合成, 亚精胺, 代谢途径解析