Zhao Jing, Zhong Chun-Jiu
Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai 200032.
Neurosci Bull. 2009 Apr;25(2):94-9. doi: 10.1007/s12264-009-1113-y.
Transketolase (TK), a thiamine diphosphate (ThDP)-dependent enzyme, catalyzes several key reactions of non-oxidative branch of pentose phosphate pathway. TK is a homodimer with two active sites that locate at the interface between the contacting monomers. Both ThDP and bivalent cations are strictly needed for TK activation, just like that for all ThDP-dependent enzymes. TK exists in all organisms that have been investigated. Up to now, one TK gene (TKT) and two transketolase-like genes (TKTL1 and TKTL2) have been identified in human genome. TKTL1 is reported to play a pivotal role in carcinogenesis and may have important implications in the nutrition and future treatment of patients with cancer. Researchers have found TK variants and reduced activities of TK enzyme in patients with neurodegenerative diseases, diabetes, and cancer. Recent studies indicated TK as a novel role in the prevention and therapy of these diseases.
转酮醇酶(TK)是一种依赖硫胺素二磷酸(ThDP)的酶,催化磷酸戊糖途径非氧化分支的几个关键反应。TK是一种同型二聚体,有两个活性位点,位于相互接触的单体之间的界面处。与所有依赖ThDP的酶一样,TK激活严格需要ThDP和二价阳离子。在所有已被研究的生物体中都存在TK。到目前为止,人类基因组中已鉴定出一个TK基因(TKT)和两个转酮醇酶样基因(TKTL1和TKTL2)。据报道,TKTL1在致癌过程中起关键作用,可能对癌症患者的营养和未来治疗具有重要意义。研究人员发现,神经退行性疾病、糖尿病和癌症患者存在TK变体且TK酶活性降低。最近的研究表明,TK在这些疾病的预防和治疗中具有新作用。