Researchers at Case Western Reserve University and University Hospitals in the US have identified an enzyme that blocks insulin produced in the body, a discovery that could provide a new target to treat diabetes.

The study, published in the journal Cell, focuses on nitric oxide, a compound that dilates blood vessels, improves memory, fights infection and stimulates the release of hormones, among other functions.

How nitric oxide performs these activities has long been a mystery.

The researchers discovered a novel “carrier” enzyme (called SNO-CoA-assisted nitrosylase, or SCAN) that attaches nitric oxide to proteins, including the receptor for insulin action.

They found that the SCAN enzyme was essential for normal insulin action, but also discovered heightened SCAN activity in diabetic patients and experimental models with diabetes.

Experimental models without the SCAN enzyme appeared to be shielded from diabetes, suggesting that too much nitric oxide on proteins may cause such diseases.

“We show that blocking this enzyme protects from diabetes, but the implications extend to many diseases likely caused by novel enzymes that add nitric oxide,” said lead researcher Jonathan Stamler from the Case Western Reserve School of Medicine. “Blocking this enzyme may offer a new treatment.”

Given the discovery, the next steps could be to develop medications against the enzyme.

Excessive nitric oxide has been implicated in many diseases, but the ability to treat it has been limited because the molecule is reactive and can’t be targeted specifically.