Here's a chart of the variations in amino acid sequence on the A and
B chains of different species. (from W. Ganong, Review of medical physiology
1989, and Canine and Feline Endocrinology and
Reproduction). You can see that dog and pork insulin have identical
amino acid sequences. Cat and human insulin vary in all 4 positions,
whereas cat and beef insulin vary in one position.
Acid Chain and Position
Ala = alanine
His = histidine
Ile = isoleucine
Thr = threonine
Val = valine
The structure of bovine insulin, showing the amino acid sequence of the
two chains and the cross-linkages. The bold positions are where
substitutions usually occur. From Lehninger: Principles of Biochemistry. 1982. Pg. 134
- Insulin structure information and image
from Lehninger: Principles of Biochemistry. Albert L. Lehninger,
Editor. Worth publishers, Inc. 1982.
- Review of Medical Physiology Fourteenth
Edition, 1989. William F. Ganong, Editor. Appleton &
Updated November 2000
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