Insulin, sugar, and evolution [Discovering Biology in a Digital World]

In my last post, I wrote about insulin and interesting features of the insulin structure. Some of the things I learned were really surprising. For example, I was surprised to learnhow similar pig and human insulin are. I hadnt considered this before, but this made me wonder about the human insulin we used to give to one of our cats. How docat and human insulin compare?

It turns out, that all vertebrates produce insulin, even frogs and zebra fish. Human preproinsulin is only 110 amino acids long and evenhuman and fish insulin are pretty similar. Of course, this observation only leads to more questions. Like why? Why would fish insulin and human insulin be similar at all?

One clue comes from insulins function. Many cells require insulin for growth. Another clue comes from the insulin structure. A key feature of the insulin protein is apair of disulfide bonds that hold the two chains (A and B) together.

Disulfide bonds between chains A and B in human insulin, PDB ID 1TRZ

Continued here:
Insulin, sugar, and evolution [Discovering Biology in a Digital World]