Chong Isaac K W, Ho Wing S
Department of Pharmacy, Liverpool John Moores University, UK.
Protein Pept Lett. 2013 Sep;20(9):970-6. doi: 10.2174/0929866511320090002.
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is known to interact with different biomolecules and was implicated in many novel cellular activities including programmed cell death, nuclear RNA transport unrelated to the commonly known carbohydrate metabolism. We reported here the purification of GAPDH from Chironomidae larvae (Insecta, Diptera) that showed different biologic activity towards heavy metals. It was inhibited by copper, cobalt nickel, iron and lead but was activated by zinc. The GAPDH was purified by ammonium sulphate fractionation and Chelating Sepharose CL-6B chromatography followed by Blue Sepharose CL-6B chromatography. The 150-kDa tetrameric GAPDH showed optimal activity at pH 8.5 and 37°C. The multiple alignment of sequence of the Chironomidae GAPDH with other known species showed 78 - 88% identity to the conserved regions of the GADPH. Bioinformatic analysis unveils substantial N-terminal sequence similarity of GAPDH of Chironomidae larvae to mammalian GADPHs. However, the GADPH of Chironomidae larvae showed different biologic activities and cytotoxicity towards heavy metals. The GAPDH enzyme would undergo adaptive molecular changes through binding at the active site leading to higher tolerance to heavy metals.
已知3-磷酸甘油醛脱氢酶（GAPDH）可与不同的生物分子相互作用，并参与许多新的细胞活动，包括程序性细胞死亡、与常见碳水化合物代谢无关的核RNA转运。我们在此报告了从摇蚊幼虫（昆虫纲，双翅目）中纯化出的GAPDH，它对重金属表现出不同的生物活性。它受到铜、钴、镍、铁和铅的抑制，但被锌激活。通过硫酸铵分级分离、螯合琼脂糖CL-6B层析，随后进行蓝色琼脂糖CL-6B层析对GAPDH进行纯化。150 kDa的四聚体GAPDH在pH 8.5和37°C时表现出最佳活性。摇蚊科GAPDH与其他已知物种的序列多重比对显示，与GADPH的保守区域有78 - 88%的同一性。生物信息学分析揭示了摇蚊幼虫GAPDH的N端序列与哺乳动物GADPH有很大的相似性。然而，摇蚊幼虫的GADPH对重金属表现出不同的生物活性和细胞毒性。GAPDH酶会通过在活性位点结合而发生适应性分子变化，从而导致对重金属有更高的耐受性。
