1. Systemic arterial blood contains:
Oxygen Transport
Systemic arterial blood contains:
~19.8 ml O2/100 ml blood
19.5 ml O2
bound to Hb
98.5%
0.3 ml O2
in solution
in plasma
1.5%

2. Respiratory Pigments
Protein, containing a metal, with or without a prosthetic group
Increases the O2-carrying capacity of the blood
Can function continuously or only at low oxygen tensions
Play other roles besides O2 transport

3. Common characteristics:
Reversibly bind O2
Bind O2 with proper affinity

4. Hemoglobin

6. each subunit has a porphyrin heme moiety
Human Hb
M.W. = 64,450
4 subunits - 2 a and 2 b
each subunit has a porphyrin heme moiety
containing one Fe2+
each Fe2+ can bind one O2
Hb + O2
HbO2
HbO4 + O2
HbO6
HbO2 + O2
HbO4
HbO6 + O2
HbO8

7. P50

9. Sigmoid shape due to cooperativity in O2 binding sites

10. Pigment Description M.W. Occurrence
Respiratory Pigments
Pigment Description M.W. Occurrence
Hemoglobin Iron w/ porphyrin 17,000 - Most widely dist.
(Hb) 3,000,000 annelids, molluscs
arthropods, verts.
Chlorocruorin “ 3,400,000 Polychaetes
Hemerythrin Iron w/o porphyrin 66,000 - Sipunculids, poly-
120,000 chaetes, priapu-
lids,brachiopods
Hemocyanin Copper 400,000 - Molluscs,
(HCy) 6,680,000 arthropods
Hemovanadin Vanadium Tunicates

11. Bohr Effect - Decrease in O2 affinity (increase in P50)
with decrease in pH (increase in [H+])

12. CO2 effect - decrease in O2 affinity with
an increase in PCO2

13. Temperature effect - decrease in O2 affinity with an increase in temp.

14. Root Effect - Fish hemoglobin demonstrates
a decrease in O2-carrying capacity with a
decrease in pH
% Saturation
100
PO2 (mm Hg)
160
pH 7.4
pH 6.8