A structural arrangement of 6-12 transmembrane domains is common among mammalian proteins that transport small organic molecules.
These connecting regions may account for the differing activities of the bacterial and mammalian proteins.
Similarly, 13 of the 16 selected mammalian proteins were either mammal-specific or vertebrate-specific (Table 2).
In fact, proteomics studies have identified thousands of acetylated mammalian proteins.
This family consists of several mammalian proteins that are around 250 amino acids in length.
This would seem to break the rule of "co-translational" translocation which has always held for mammalian proteins targeted to the ER.
But its chief weapon against an epidemic was a regulation it issued preventing farmers from feeding most forms of mammalian protein to cattle and sheep.
Moreover, a mammalian protein is sometimes not correctly modified in yeast (e.g., missing phosphorylation), which can also lead to false results.
Percentages indicate the identity shared by the human protein and the respective mammalian protein.
Rods and cones use rhodopsin, a mammalian protein in the same family.