Isolation of a lectin from apple pollen. Lectins are present in plants Dissertation

Isolation of a lectin from apple pollen. Lectins are present in plants (and animals), they are proteins that that bind to carboh - Dissertation Example So a study on biochemical, physiological and molecular levels is required to explore the importance of Lectin in the plant cell. Lectin is present in many forms in the plant cells. The pollen grains of the apple are found to have some group of Lectin. These Lectin are heterodimers and have a great affinity for the glycopeptides with a molecular weight of 30,000 Daltons and have two subunits with N-acetyl glucosamine residues. Arabinose is found linked to the polypeptide chain as ?-L-arabinofuranosides through the hydroxylproline residues. (Sharon and Lis, 2007). The glycopeptides are found to contain lesser amount of serine, S-carboxyl methyl cysteine and other amino acids such as glycine as major amino acids. Cysteine (16%), Hydroxyproline (11%) and Glycine (12%) is the major amino acid composition of lectin. Lectin agglutinates the cells and precipitates the complex carbohydrates. The lectin has Arabinose monosachharide (93%) and Galactose (7.5%) of the total 37% carbohydrate conte nt of lectin. (Sharon and Lis, 2007). ... Second thing to look upon is whether it is bound to any organelle or free protein. The Ammonium sulfate precipitation can be carried out after cell lysis. The cell disruption can be performed in many ways. Using mortar and pestle, sonication are some of the simple steps that can be easily practiced in lab. (Scopes, 1994).The cells are crushed using the saline buffer in order to maintain the pH. The protein extraction procedures are carried out in a cold room usually at 4 Â °C, in order to preserve the active part of the protein. The Ammonium sulfate precipitation is then carried out. Ammonium sulfate precipitation is a salting out process where the proteins are precipitated by adding ammonium sulfate at saturation constant. The saturation level varies for every protein and hence this phenomenon is widely used for the separation of the protein from the cell debris. The percentage of purification achieved at this stage is around 30 – 40%. Ammonium sulfate precipitation method i s repeated to increase the concentration of the protein in the sample. After ammonium sulfate precipitation, the ammonium sulfate salt is removed from the protein by using the neutralizing buffer. The dialysis is the next downstream processing step. Dialysis is done using a semi-permeable membrane bag that has a very small pore size of 20 Â µm. Dialysis is done overnight in the saline to concentrate the protein. For further purification of the protein, chromatographic techniques are used. Affinity chromatography, anion exchange chromatography, gel permeation chromatography are some of the most commonly used chromatographic techniques for this protein. Same type of lectin is present in seeds and pollen grains hence the same procedure for the seed lectin extraction can be followed for the pollen