Title:Glyceraldehyde-3-phosphate Dehydrogenase from Chironomidae Showed Differential Activity Towards Metals
Volume: 20
Issue: 9
Author(s): Isaac K.W. Chong and Wing S. Ho
Affiliation:
Keywords:
Chironomidae, Glyceraldehyde-3-phosphate Dehydrogenase (GAPDH), heavy metal, Zinc, copper.
Abstract: 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.
