S-sulfanyl-L-cysteinyl-[cysteine desulfurase] + L-alanine => L-cysteinyl-[cysteine desulfurase] + L-cysteine
s-sulfanyl-l-cysteinyl-[cysteine desulfurase] + l-alanine => l-cysteinyl-[cysteine desulfurase] + l-cysteine