Fig. 3From: Insulins for the long term management of diabetes mellitus in dogs: a reviewThe TR transition between insulin hexamers. A Schematic representation of the three insulin hexamers. T state protomers are shown in red, and R state protomers in blue. Axial zinc ions are shown in purple. B Corresponding ribbon representation of the crystal structures. From Berenson et al. 2011 [8]Back to article page