Biology 2601A/B Lecture Notes - Lecture 15: Hemocyanin, Respiratory Pigment, Porphyrin
10 Dec 2018
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Gases that combine chemically with other molecules don"t contribute to partial pressure: they are no longer free gasses dissolved in solution. Every time an oxygen binds to hemoglobin it doesn"t contribute to the partial pressure: keeps po2 in blood low the difference in po2 is what drives gas diffusion. Heme is a porphyrin ring complex with an iron atom: porphyrin is trapping the iron in the centre, higher oxygen availability = more likely to bind. Myoglobin is a monomeric protein with a single heme molecule. *a metal transiently binds with the oxygen, it doesn"t react with it. Hemocyanins are blue, copper containing, non-porphyrin proteins that have multiple oxygen binding sites; they"re found extracellularly is some molluscs and arthropods. Hemocyanins don"t use iron, they use copper which is bound to hemocyanin protein: not found in red blood cells, free floating protein found in hemolymph, turns blue when oxygenated.
