Although part of the coenzyme A pathway, vanin 1 (also known as pantetheinase) sits on the cell surface of many cell types as an ectoenzyme, catalysing the breakdown of pantetheine to pantothenic acid (vitamin B₅) and cysteamine, a strong reducing agent.

Vanin 1 was initially discovered as a protein involved in the homing of leukocytes to the thymus. Numerous studies have shown that vanin 1 is involved in inflammation, and more recent studies have shown a key role in metabolic disease.

Here, the X-ray crystal structure of human vanin 1 at 2.25 Å resolution is presented, which is thefirst reported structure from the vanin family, as well as acrystal structure of vanin 1 bound to a specific inhibitor. These structures illuminate how vanin 1 can mediate its biological roles by way of both enzymatic activity and protein–protein interactions. Furthermore, it sheds light on how the enzymatic activity is regulated by a novel allosteric mechanism at a domain interface.