And attached onto this acid carrier protein is a phosphopancy thion molecule, which is a vitamin B five derivative. So, to see exactly what we mean, let's take a look at the following diagram. So, we have the fatty acid synthase shown in red, and that contains seven catalytic sites which are not shown. In addition to those seven catalytic sites, we also have a domain we call the Acyl carrier protein domain. And that's shown in green. And attached onto this ACL carrier protein, is the vitamin B five derivative we call phosphopancythione.