Expression of b5 and b5R immunoreactive protein in three human livers with non-synonymous cSNPs in either CYB5A or CYB5R3. Representative immunoblots shown for assays done in duplicate; 30 µg microsomal protein loaded and probed with rabbit polyclonal anti-human b5 or anti-human b5R antibody. (a) wild-type (WT) CYB5A homozygote, and S5A heterozygote in CYB5A showing absence of b5 expression at 17 kDa. Additional bands (22 and 54 kD) represent as yet unidentified proteins that cross-react with anti-human b5 antibody. (b) wild-type CYB5R3 homozygote, and R59H heterozygote in CYB5R3, showing modest but significantly decreased b5R protein expression (37 kDa), when normalized to β-actin (42 kDa). Separate blot with wild-type wild-type CYB5R3 homozygote, and R297H heterozygote in CYB5R3, showing two bands for the R297H subject.