Further characterization and structural studies on human placenta lectin.
The properties of a previously purified beta-galactoside-binding lectin of human placenta were studied in detail. Isoelectric focusing gave multiple bands around pH 4.9, although the lectin preparation was homogenous in SDS-polyacrylamide gel electrophoresis. High-performance gel chromatography suggested that the lectin exists mainly as the monomer and that a small fraction forms a dimer. From all the criteria examined, human placenta lectin resembles one of the chick lectins obtained from embryonic skin or adult intestine (subunit molecular weight: 14,000). The lectin was inactivated by thiol-modifying reagents, p-chloromercuribenzoic acid and N-ethylmaleimide. Reduced and carboxymethylated lectin contained five carboxymethylated cysteines per subunit, and five free thiol groups were titrated by using 5,5'-dithio-bis(2-nitrobenzoic acid). Preliminary sequence analysis showed the presence of a region highly homologous to the corresponding region of the chick lectin (13 identical residues out of 18 from number 70 to 87 of the chick lectin), suggesting a close evolutionary relation between these lectins and the importance of this conserved region in the function of the lectins.
D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D003488:Cyanogen Bromide; D005697:Galactosides / Q000378:metabolism; D006801:Humans; D007463:Iodobenzoates; D007526:Isoelectric Point; D037102:Lectins / Q000032:analysis*; D008970:Molecular Weight; D010920:Placenta / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet; D013438:Sulfhydryl Compounds / Q000494:pharmacology
D005697:Galactosides; D007463:Iodobenzoates; D037102:Lectins; D013438:Sulfhydryl Compounds; C008154:2-iodosobenzoic acid; D003488:Cyanogen Bromide