Muscle Enzyme Explains Weight Gain in Middle AgePosted on May 9th, 2017 by Dr. Francis CollinsThe struggle to maintain a healthy weight is a lifelong challenge for many of us. An NIH-led team recently discovered that the normal process of aging causes levels of an enzyme called DNA-PK to rise in animals as they approach middle age. To see if reducing DNA-PK levels might rev up the metabolism, the researchers turned to middle-aged mice. They found that a drug-like compound that blocked DNA-PK activity cut weight gain in the mice by a whopping 40 percent! The researchers suspected that an increase in DNA-PK in middle age might lead directly to weight gain.