Detection and estimation of 3,4-dehydroproline

A method has been described for the detection and estimation of 3,4-dehydroproline using initial oxidation with isatin or H2O2 and subsequent reaction with p-dimethylamino benzaldehyde (Ehrlich reagent). The method is sensitive enough to detect as low as 0.6 micrograms of 3,4-dehydroproline/sq. cm on paper chromatogram. 3,4-dehydroproline could also be estimated by the classical H2O2-oxidation procedure employed for hydroxyproline apparently yielding the same chromophore on a molar basis. However, when estimated by the chloramine-T oxidation method, its sensitivity was only 1/100th of that of 4-hydroxyproline. The usefulness of these procedures in the detection and estimation of 3,4-dehydroproline has been described.