Fig. 3: Milk β-lactoglobulin proteins identified from ancient dental calculus of individuals from Sudan and Kenya.
From: Ancient proteins provide evidence of dairy consumption in eastern Africa

A 3D model of β-lactoglobulin showing location of species variant sites. B Variations in the amino acid sequence at position 71 and 148 can be used to distinguish between Bos, Ovis and Capra. C Spectrum for TPEVDKEALEK specific to Capra from individual Z708. D Spectrum for TPEVDDEALEKFDK from individual DA323. The deamidation of asparagine results in its conversion to aspartic acid so an unmodified (D) is indistinguishable from (de.N); therefore, this milk peptide is identified as Bovinae/Ovis. The 3D image of β-lactoglobulin is from SwissModel [https://swissmodel.expasy.org/repository/uniprot/P02754].