Learning 1 of Cancer's Tricks (IMAGE) California Institute of Technology Caption A computational model depicts a PFK1 enzyme with the sugar GlcNAc attached (left). Comparing this model to that showing PFK1 complexed to a molecule that activates the enzyme (right) suggests how addition of GlcNAc may inhibit enzymatic activity. Credit Caltech/Yi et al. 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.