The controversy centres around a family of enzymes known as heme enzymes, due to the presence of a heme group in their active site. At the centre of the heme cofactor is an iron (Fe) atom, which ...

CHAMPAIGN, Ill. -- When animals metabolize food or when plants photosynthesize it, electrons are moved across cell membranes. The "extension cords" of this bioelectrical circuit are mostly ...

Histidine is an amino acid which can be obtained through hydrolysis of proteins. An abundant source of histidine is hemoglobin, which contains 8.5%. The human body is unable to synthesize this amino ...

Proceedings of the National Academy of Sciences of the United States of America, Vol. 95, No. 26 (Dec. 22, 1998), pp. 15177-15182 (6 pages) The FixL proteins are biological oxygen sensors that ...