Purification of peanut lectin using guar gum as an affinity ligand

Applications of Alginate in Bioseparation of Proteins

Alginate is a polysaccharide that is a block polymer consisting of block units of guluronic acid and mannuronic acid. It shows inherent biological affinity for a variety of enzymes such as pectinase, lipase, phospholipase D, a and ss amylases and glucoamylase. Taking advantage of its precipitation with Ca2+ and the above-mentioned property, alginate has been used for purification of these enzymes by affinity precipitation, aqueous two phase separation, macroaffinity ligand facilitated three phase partitioning, immobilized metal affinity chromatography and expanded bed affinity chromatography. Thus, this versatile marine resource has tremendous potential in bioseparation of proteins.

Leveraging protein purification strategies in proteomics

The proteomic studies, although, tend to be analytical in nature, yet many strategies of preparative protein purification can be usefully employed in such studies. This review points out the importance of purification techniques which are capable of dealing with samples which are suspensions rather than clear solution, e.g. aqueous two phase partitioning, three phase partitioning, expanded bed chromatography, etc. The review also outlines the potential of non-chromatographic techniques in dealing with fractionation of proteomes. Separation protocols which can deal with post-translationally modified (PTM) proteins are also considered.

A galactose-specific lectin from the red marine alga Ptilota filicina

A lectin from the red marine alga Ptilota filicina (PFL) was isolated by affinity chromatography on cross-linked guar gum. PFL agglutinated native and papain-treated human erythrocytes with preference for type O erythrocytes. The lectin was inhibited by galactose and its derivatives. The most potent inhibitors were p-Nitrophenyl-N-acetyl-alpha- and beta-D-galactosaminide. Porcine stomach mucin, bovine submaxillary gland mucin and asialo bovine mucin were also inhibitory. The M(r) of PFL, determined by gel filtration, was 56,900. SDS-PAGE gave one band with a subunit M(r) of 19,320, indicating the native protein to be a trimer of apparently identical subunits. PFL was shown to be rich in acidic and hydroxyl amino acids but low in basic amino acids. The ten N-terminal amino acids were Asx-Thr-Lys-Thr-Leu-Leu-Ala-.