Characterization of acetylcholinesterase from Korean electric ray and comparison with Torpedo californica

Abstract

This study has been undertaken to examine the acetylcholinesterase (AChE) of electric organ from Korean electric ray (Narke japonica). Korean electric ray was caught at Chungmu sea and transported to the laboratory, where electric organs were removed and stored at -70°C until used. Acetylcholinesterase (AChE) of electric organ was purified by affinity column that was prepared with dicaproyl-methylpyridinium linked to Sepharose 4B. Upon purification, the specific activities in Ellman unit were increased by 52 and 39 times for high salt soluble AChE (HSSE, 870.86 ΔOD/min/gram of tissue) and detergent soluble AChE(DSE, 105.42 ΔOD/min/ gram of tissue), respectively. Each subunit of AChE separated by SDS polyacrylamide gel electrophoresis (SDS-PAGE) was transferred to immobilon P by western blotting and detected by mAbs raised against each subunit of AChE from electric organ of Torpedo californica. Collagenic tails of AChE from Narke japonica were identified by monoclonal antibody specific to collagenic tail of AChE from Torpedo californica, likewise 103 Kd protein of AChE from Narke japonica was detected by monoclonal antibody specific to 103 Kd of AChE from Torpedo californica. However, molar ratio of three subunits of AChE from Narke japonica is different from that of Torpedo californica. Furthermore, catalytic subunit of AChE from Narke japonica was not identified by monoclonal antibody specific to catalytic subunit of AChE from Torpedo californica. These results showed differences in molecular structure of AChE from Narke japonica and AChE from Torpedo californica even though they showed same enzymatic activities.