Angiotensin-converting enzyme 2, or ACE2 for short, is like a little "lock" that can be found on the outside of some cells in the body. It's a special type of protein that helps your body regulate your blood pressure and keeps your heart working properly.
Sometimes, your body makes another protein called angiotensin II that can cause problems, like making your blood vessels narrow and putting extra stress on your heart. But when angiotensin II meets up with ACE2, it's like putting a key into the lock. This can stop angiotensin II from causing trouble and actually help protect you from heart disease.
However, ACE2 has been in the news recently because of the coronavirus. This virus is able to attach to ACE2 and sneak into your cells, causing respiratory problems and other symptoms. So while ACE2 is usually a good thing, it's important to protect yourself from the coronavirus by washing your hands, wearing a mask, and practicing social distancing.