Cereal Chem 1973 | Studies on Corn Proteins. V. Reduced Color Response of Opaque-2 Corn Protein to the Biuret Reagent, and Its Use for the Rapid Identification of Opaque-2 Corn.

Cereal Chem 50:184 - 190. | VIEW ARTICLE
Studies on Corn Proteins. V. Reduced Color Response of Opaque-2 Corn Protein to the Biuret Reagent, and Its Use for the Rapid Identification of Opaque-2 Corn.

P. S. Misra, R. Barba-Ho, E. T. Mertz, and D. V. Glover. Copyright 1973 by the American Association of Cereal Chemists, Inc.

The biuret method of Johnson and Craney for the determination of protein in corn (maize) gave reduced color values when applied to opaque-2 corn, a mutant with low zein content. Further tests with normal and opaque-2 corn protein fractions showed that the specific intensity of the biuret reaction is nearly four times greater with zein than with glutelin. Because of the reversal in the zein:glutelin ratio in opaque-2 corn, the biuret absorbance per unit of Kjeldahl nitrogen is 50 to 80% of that in normal corn. This color reduction can be used for the rapid identification of opaque-2 corn in corn breeding programs.