A rapid and sensitive method for the analysis of cyanophycin

A method has been devised for the quantitative analysis of cyanophycin, based on H-1 nuclear magnetic resonance (NMR) spectroscopy, allowing determination of the nitrogen status of cyanobacteria. Cyanophycin is extracted with minimal washing from small volumes of cells and quantified by integration of the NMR peak attributed to the protons attached to the delta -carbon of arginine. Linear relationships were found between the amount of cyanophycin determined by this method and both known concentrations of cyanophycin solutions and the amount of cyanophycin determined using the standard chemical arginine assay. (C) 2001 Elsevier Science B.V. All rights reserved.