L-aspartyl-L-lysine(out) = L-aspartyl-L-lysine(in)
l-aspartyl-l-lysine(out) = l-aspartyl-l-lysine(in)
L-aspartyl-L-lysine(out) = L-aspartyl-L-lysine(in)
l-aspartyl-l-lysine(out) = l-aspartyl-l-lysine(in)