Respiratory Pigments

Cooperativity

1st molecule of O2 is not bound readily, but after first, it changes shape so others bind more readily, increased affinity

Hemocyanin

2nd most common, mollusks and anthropods. Colorless when not bound to oxygen, bright blue when oxygenated

4 types of respiratory pigments

Hemoglobin, hemocyanin, hemerythrin, and chlorocruorin

Respiratory pigments

binds to oxygen and consists of a protein molecule and an associated metal ion

increases rate of reaction

carbonic anhydrase

Iron

center of each heme sub unit

Hemerythrin

marine invertebrate phyla. Oxygenated=pink deoxygenated= colorless

Hb A

most common, 2 alpha subunits and 2 beta subunits held together noncovalently. each subunit reversibly binds to a single O2 molecule

hemoglobin

most common, many invertebrates and all vertebrates. the unit is a globin protein that has an associated heme group. The iron atom= red oxygenated blood and blue deoxygenated. vertebrates= in RBC, invertebrates= blood cells or free in plasma

Chlorocruorine

only in marine animals. Dilute form= green. Concentrated form=red

Myoglobin

stores oxygen in muscle tissue

Bohr effect

the ability of hemoglobin to bind oxygen decreases with decreasing pH