The determination of epsilon-amino groups in soluble and poorly soluble proteinaceous materials by a spectrophotometric method using trinitrobenzenesulfonic acid.
A procedure using 2,4,6-trinitrobenzenesulfonic acid (TNBS) for the determination of epsilon-amino groups in soluble and poorly soluble proteinaceous materials is presented. The major modification from previous procedures is an extended TNBS reaction time to allow a stoichiometric reaction with amino groups. In addition, autoclave hydrolysis is used to assure sample dissolution for spectrophotometric measurements. The assay accuracy was evaluated by determining epsilon-amino groups of insulin and bovine albumin. The determinations differed from literature values by < or = 3.3%. The epsilon-amino group content of Type B gelatin was found to be 33.0 mol/gelatin molecule of 1000 residues and is in agreement with similar source gelatins and collagen. The coefficient of variation for determinations on all three materials was < or = 5.3%. The assay should be applicable to a broad range of proteinaceous materials.
Bubnis
W A
WA
Philadelphia College of Pharmacy and Science, Department of Pharmaceutics, Pennsylvania 19104.
Ofner
C M
CM
D000418:Albumins / Q000032:analysis; D000588:Amines / Q000032:analysis*; D000818:Animals; D002417:Cattle; D005780:Gelatin / Q000032:analysis; D006801:Humans; D007328:Insulin / Q000032:analysis; D008970:Molecular Weight; D011506:Proteins / Q000032:analysis*; D012680:Sensitivity and Specificity; D012995:Solubility; D013053:Spectrophotometry / Q000379:methods; D013997:Time Factors; D014302:Trinitrobenzenesulfonic Acid
D000418:Albumins; D000588:Amines; D007328:Insulin; D011506:Proteins; D014302:Trinitrobenzenesulfonic Acid; D005780:Gelatin