Symptoms include daytime drowsiness, fatigue, and diminished concentration. SAD usually afflicts adults and is four times more common in women than men. An example is the food additive thiodipropionic acid.
Examples are bone marrow cells and the cells lining the gastrointestinal tract.
A sulfhydryl compound contains one or more sulfhydryl groups. Examples include vitamin B-1, the amino acid cysteine, and the triple amino acid reduced glutathione. It is the fifth most common protein in the human body. Intracellular cytoplasmic SOD generally contains zinc and copper, while mitochondrial SOD contain manganese. One nerve cell stimulates another one to fire an electric pulse by secreting special chemicals called neurotransmitters into the synapse between the cells.