Passage III

Transferrin is a blood protein. When in the presence of iron ions (), each transferrin molecule will bind with 2 . Iron Chelators are used to remove excess iron in the blood because they can bind with and thereby remove from transferrin.

Transferrin bound to strongly absorbs light at a wavelength of 466 nanometers (nm), but unbound transferrin and unbound do not. Three experiments were done using a colorimeter (a device that measures a solution's absorbance of light) to study the removal of from transferrin by iron chelators.

Experiment 1

Seven solutions (Solutions 1-7) were made, all with an initial unbound transferrin concentration of 100.0 micromoles per liter (μM), but each with a different initial unbound concentration. The solutions were incubated at 37°C for 30 min. A test tube containing a sample of Solution 1 was placed in the colorimeter. The colorimeter was adjusted such that the absorbance reading measured at 466 nm for Solution 1 at 37°C was 0.00. The absorbance at 466 nm of each of Solutions 2-7 at 37°C was then measured (see Table 1).

Experiment 2

For each of 4 trials, 0.0010 mL of solution that contained 10 millimoles of 1 of 4 iron chelators was added to 3 mL of Solution 5. The absorbance at 466 nm was then monitored at 37°C over the next 4,000 sec (see Figure 1).

Experiment 3

The deferiprone trial in Experiment 2 was repeated twice, except that one trial was carried out at 25°C and the other trial was carried out at 32°C (see Figure 2).