Mammalian beta-adrenergic receptors. Structural differences in beta 1 and beta 2 subtypes revealed by peptide maps.

Lefkowitz and colleagues showed that there are two different types of beta receptors, distinguishing them as Beta-1 and Beta-2. They noticed that each has specific pharmacological characteristics. Order of authorship in the original publication: Stiles, Strasser, Caron, Lefkowitz. Digital facsimile from PubMedCentral at this link.

In 2012 Lefkowitz shared the Nobel Prize in Chemistry with Brian K. Kobilka "for studies of G-protein-coupled receptors."

(Thanks to Juan Weiss for this reference and its interpretation.)