compound specific carbon from sperm whale skin tissue 
   Ruiz-Cooley, PK Koch, MD McCarthy, et al (UCSC) 
   version: 2016-08-02 
   This data resulted in Ruiz-Cooley et al (2014) PLoSONE 
     Average Non-Essential Amino Acids: alanine, aspartate+aspartamine, glutamate+glutamine, tyrosine 
     Average Essential Amino Acids: leucine, phenylalanine, valine