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一、多胺概述 多胺是一类多阳离子的脂肪族胺。广泛存在于生物界。生理性多胺主要有精脒(spd),精胺(sp)及其前体腐胺(pu)。原核细胞一般只含pu和spd。眞核细胞还有sp。它们的化学结构如图1所示。多胺是L-鸟氨酸及L-蛋氨酸代谢的衍生物(图2)。哺乳动物细胞的pu是鸟氨酸脱羧酶(ODC)催化鸟氨酸脱羧而求。ODC以磷酸吡哆醛为辅基。除了前列腺外,多数成年休止的组织细胞ODC活性很低,它是多胺生物合成的限速酶,其半衰期是已知的眞核细胞酶中最短的,一般为20分钟右左。在生长快的器官和肿瘤组织中ODC活
Polyamine Summary Polyamines are a class of polycationic aliphatic amines. Widely existing in the biological world. Physiological polyamines are mainly spermidine (spd), spermine (sp) and its precursor putrescine (pu). Prokaryotic cells generally contain only pu and spd.眞 nuclear cells also sp. Their chemical structure is shown in Figure 1. Polyamines are derivatives of L-ornithine and L-methionine metabolism (Figure 2). The pu of mammalian cells is ornithine decarboxylase catalyzed by ornithine decarboxylase (ODC). ODC uses pyridoxal phosphate as a prosthetic group. In addition to the prostate, most adult resting tissue cells have very low ODC activity and are the rate-limiting enzymes for polyamine biosynthesis. Their half-lives are known to be the shortest of the nucleocapsid enzymes, typically about 20 minutes. ODC is alive in rapidly growing organs and tumor tissues