hemefree
Hemefree, or apo-form, describes a protein that lacks its heme cofactor. Heme, an iron-containing porphyrin, is essential for the function of many proteins including hemoglobins, myoglobins, cytochromes, catalases, and peroxidases. When heme is absent, the protein is an apoprotein, and its properties may differ markedly from the holo form that contains heme.
Heme binding commonly stabilizes structure and enables catalytic or electron-transfer activity. In many cases, apo-proteins are
Common examples include apomyoglobin, apocytochrome c, and other apoproteins studied to understand heme insertion. Maturation pathways
Detection and study rely on spectroscopy, where the Soret band near 400 nm disappears in apo-forms; reconstitution