Mass Spectrum (IMAGE) Moscow Institute of Physics and Technology Caption This is a mass spectrum of peptide fragments [from a Dmx?like 2 protein] showing a point mutation. The red indicates the position where an amino acid residue substitution (P for S) occurred. It also marks the peaks in the mass spectrum that confirm this substitution. Credit Moscow Institute of Physics and Technology Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.