 Abstract cyanophysin is a bacterial biopolymer used for storage of fixed nitrogen. It is composed of a backbone of l-aspatate residues with l-arginines attached to each of their side chains. Cyanophysin is produced by cyanophysin synthetase 1, C-PHA1, using ARGE, ASP and ATP, and is degraded in two steps. First, cyanophysinase breaks down the backbone peptid bonds, releasing arspage dipeptides. Then, these dipeptides are broken down into free arsp and ARGE by enzymes with isospatial dipeptidase activity. Two bacterial enzymes are known to possess promiscuous isospatial dipeptidase activity, isospatial dipeptidase, EDA, and isospatial aminopeptidase, IAA. We performed a bioinformatic analysis to investigate whether genes for cyanophysin metabolism enzymes cluster together or are spread around the microbial genomes. This article was offered by Tye Sharon and T. Martin Schmein. We are article.tv, links in the description below.