Estimation of protamine and insulin in protamine zinc insulin

Abstract

Insulin can be separated from protamine by paper chromatography developing with the upper phase of a mixture of n-butanol, glacial acetic acid and water (3:1:4 by vol.). A dye such as bromocresol green is used for locating the zones. The concn. of protamine and of various proteins in a soln. can be estimated on filter paper by retention analysis with a suitable dye, e.g. erythrosine. The area of the unstained wedge formed above the protein spot is proportional to the amt. of protein present. The method can be used to estimate the amt. of protamine in protamine zinc insulin after removal of insulin by paper chromatography. Data are recorded on the composition of a number of suspensions of protamine zinc insulin and on the distr. of the components between the phases of the suspension.