Model of Insulin.

"Insulin is a peptide hormone, produced by beta cells of the pancreas, and is central to regulating carbohydrate and fat metabolism in the body."
-http://en.wikipedia.org/wiki/Insulin

The cysteine residues forming disulfide bonds are represented as spheres. Model based on the Protein Data Bank entry 4INS:
http://www.pdb.org/pdb/explore/explore.do?pdbId=4INS

Model created using VMD:
http://www.ks.uiuc.edu/Research/vmd/

Successfully printed in PLA on a Makerbot Replicator2 using MakerWare 2.2.2.89, standard resolution with 3 shells and 25% infill. Use rafts and supports.