A novel protein, lysenin, that causes contraction of the isolated rat aorta: Its purification from the coelomic fluid of the earthworm, Eisenia foetida

Abstract

A novel protein that causes contraction of strips of isolated rat aorta and kills rats upon intravenous injection was purified from the coelomic fluid of the earthworm, Eisenia foetida, by the anion-exchange high-performance liquid chromatography and size-exclusion high-performance liquid chromatography. The protein had a molecular weight of 41 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Contraction of rat aorta was induced at concentrations above 10-9M. Six partial amino acid sequences of the protein revealed the absence of any significant homology to those of previously characterized proteins, suggesting that the protein is a novel biologically active protein. The protein was named lysenin. In addition, another protein with a molecular weight of 42 kDa, whose amino acid sequence resembled that of lysenin, was also isolated, but it had weak contractive activity.