Characterization of a hemoglobin-like protein from adult Haemonchus contortus

A hemoglobin-like protein was purified from supernatants of adult Haemonchu s contortus extracts by high-pressure liquid chromatography. The purified p rotein had an M-r of 33 kDa as determined by size-exclusion chromatography under nondenaturing conditions and an M-r of 19 kDa by sodium dodecyl sulfa te-polyacrylamide gel electrophoresis, suggesting the hemoglobin may exist as a dimer. The sequences of 3 peptides resulting from proteolytic digest o f the purified protein were determined and demonstrated greater than 50% id entity to the globin from Trichostronglyus colubriformis. Adult H. contortu s incubated overnight in [H-3]leucine, incorporated radioactivity into a pe ak that coeluted with parasite hemoglobin, indicating the adults synthesize hemoglobin in vitro. The L3-stage lacked hemoglobin, but the L4-stage cont ained a hemoglobin with an M-r of 19.6 kDa.