The Role of Hemoglobin in Regulation of Oxygen and Carbon Dioxide ENGS166 – Spring 2008 Presentation1 Amir Golnabi

Introduction: Oxygen: Critical to support metabolism No storage system for oxygen → constant supply Oxygen transport: Hemoglobin 280 million Hemoglobin molecules are carried in one RBC: – Hemoglobin is a large protein – Very large surface area → water attraction → changing the structure and function of the hemoglobin – Osmotic pressure in the vascular system – Coagulate of hemoglobin in some organs such as liver

Structure: α and β globin subunits: 141 vs 146 amino acids Each globin subunit is bound to a Heme molecule Heme: carbon, nitrogen, and hydrogen atoms, with a single iron ion at the center of the ring: Oxygen attracting property Red color of hemoglobin: Oxygen oxidizes the iron ion Hemoglobin Animation mestruct/heme-struct.gif

Function: Partial pressure of oxygen in lungs vs in tissues Oxyhemoglobin Oxygen-hemoglobin dissociation curve Example: at rest=40 mmHg doing exercise = 30 mmHg Sat. drops from 70% to 40% i.e. release more oxygen Sigmoidal Shape: cooperative binding mages/O2saturation2.gif

Regulation Factors: 1. Amount of PH 4. Temperature During exercise: right shift conformational change of hemoglobin: Releasing more oxygen Carbon dioxide removal