Timing is Everything (IMAGE) Sanford Burnham Prebys Caption Timing is everything. As secreted proteins age their attached complex N-glycans undergo a progressive enzymatic loss of sugar linkages, one at a time, leading to the appearance of signals of increased age that determine a protein’s life span. Credit Peter Allen, UCSB 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.