ABSTRACT
The physical and chemical properties of alfalfa mosaic virus from white clover have been studied by analytical ultra-centrifuge. The results showed that this virus sample contains five different components which possess the S_(20) values of 98s, 82s, 72s, 65s, and 36s respectively. While measured the S values we have used schlieren light system by using UV system as control. The twice changed speed method also has been used to measure the S values at different concentration of samples under different ion strength.
ABSTRACT
The concentration-dependent self-association of α-chymotrypsin is known to be influenced by various factors including the presence of small molecules and autolysis products. In this connection the effect of various amino acids on the self-association of α- chymotrypsin has been studied, as a point of interest, by measuring the sedimentation coefficient of α-chymotrypsin. The influence of an amino acid is seen to be governed by the nature of its side chain. Some amino acids do not affect the self-association of α- chymotrypsin at all while some affect it moderately and some others considerably. Functional groups such as the – OH group of Ser or the phenolic ring of Tyr do not seem to influence self-association behaviour. Based on these effects, amino acids could be categorized into 3 groups. Activity studies in the presence of amino acids indicate that the site of self-association and the active-site are probably mutually exclusive.