A study on the interaction between concanavalin A and glycogen by light scattering technique and its analytical application.

The mixture of concanavalin A (Con A) and glycogen shows strong light scattering character. Based on it, the interaction between Con A and glycogen was studied on a common spectrofluorimeter by light scattering technique. Many factors affecting the light scattering intensity (LSI), such as pH, temperature, reaction time, ion strength and the denaturing agent of protein were studied in detail. Experimental results showed that the LSI reached its maximum after mixing Con A with glycogen for about 20 min in pH 7.4 Tris-HCl buffer at 37 degrees C. The results also suggested that the conformation of Con A was critical for its unique binding affinity to glycogen. Electrostatic forces should not be the primary interaction between glycogen and Con A. Under proper experimental conditions, the determination method for glycogen by light scattering technique was developed. The glycogen determination can be performed in the range of 0.48-32.0, 0.50-32.0 and 0.32-24.0 mug/ml for Rabbit liver glycogen (RL Gly), Oyster glycogen (O Gly) and Clam Glycogen (C Gly), respectively. The influence of co-existing substances such as proteins, mono- and di-saccharides and metal ions was evaluated, and little interference came from the foreign substances. The determinations of glycogen in synthetic samples demonstrated that the recovery rate was in the range of 98.1-103% and the relative standard deviations (RSD) were lower than 5.0%.