Cloning and analysis of a cDNA encoding a human liver carboxylesterase

A human liver carboxylesterase (CE)-encoding cDNA has been cloned using synthetic Oligodeoxyribonucleotides (oligos) based on the known amino acid (aa) sequences of rabbit and rat liver CEs. The oligos hybridize specifically to DNA encoding liver CEs. The longest cDNA obtained from screening several cDNA libraries encodes about 80% of the protein and translates into an aa sequence which has a high degree of similarity with the sequences of liver CEs from other species. On hybridization to mRNA isolated from human liver, the cDNA gave a single band of about 2.0 kb consistent with its encoding a protein of < 68 kDa. DNA obtained from a number of human livers and probed with the CE cDNA gave identical hybridization patterns. These patterns were moderately complex by comparison with published data

Babesia bovis: Biosynthesis and localisation of the 12D3 antigen in bovine erythrocytes

The 12D3 antigen of Babesia bovis was found to be synthesised rapidly in cultured parasites, and localised to both the apical complex of the merozoite and the cytoplasm of the parasitised erythrocyte. Amino-terminal sequencing suggested that the nascent protein had been processed and differences between the predicted and measured molecular weights suggested post-translational modification. The major proportion of 12D3 appeared in the soluble compartment of the parasitised erythrocytes with a molecular weight consistent with no further processing. A significant proportion of the protein required extraction by sodium carbonate, suggesting association with membranous components. The timing of release of soluble 12D3 was coincident with haemoglobin release and this probably reflects a non-specific lysis of the erythrocyte. Synthesis of recombinant BV12D3 was achieved in baculovirus-infected SF9 insect epithelial cells. The product was of the same molecular weight as the native 12D3 and polyclonal antibodies raised against the recombinant protein reacted with both the recombinant and native forms of the antigen