Aging has been considered a phenomenon that can be only applied to cells or organisms. Here, we show that RecQ helicase from E. coli displays an aging phenomenon: this macromolecular motor loses its structure and function after hydrolyzing a certain number of ATP molecules. The aging process was only triggered by repeated catalytic cycles. These observations lead to a new concept: macromolecule aging. (C) 2021 Elsevier Inc. All rights reserved.