Iron in Biology: Iron Content in Ferritin, the Iron-storage Protein is a general-chemistry laboratory where the students learn and apply the principles of absorption spectroscopy, metal chelation, redox reactions, kinetics, and three-dimensional structure-function relationships to study the chemical properties of the iron-storage protein ferritin.

In this experiment, the students use the spectrophotometer to perform a trace analysis of the iron content in ferritin and to observe the kinetics of the iron-release process. First, the total amount of iron in a ferritin sample is determined by breaking apart the protein shell, and then the time course of iron released from the intact protein by the reduction of the iron-mineral core is determined. In this manner, the mechanism of the in vitro iron-release process is examined. In addition, the students are introduced to three-dimensional structure and structure-function relationships via a molecular-graphics tutorial.

Further Information:

Announcements There is significant iron contamination in the most recently obtained manufacturer's lot of DHF. To purify the DHF, use the following procedure:

Add DHF to methanol and stir. Use approximately 25 grams in 200 ml of methanol. Stir for about one hour; during this time, the methanol will turn black. Filter the yellow solid that is left behind by gravity filtration. Add water to the methanol until white crystals start coming out. Cool solution and collect the white crystals. Rinse the crystals with ice cold water. Note that this method is not technically a recrystallization since we crash out the crystals. But this procedure works with no problems.


Molecular-graphics Tutorial This molecular-graphics tutorial is used in conjunction with the laboratory experiments. It is used as an introduction to three-dimensional structure and structure-function relationships, and to give the students a better understanding of the iron-release process. The students are given a list of questions to answer before going through the tutorial, and similar questions are interspersed throughout the tutorial, along with hints to guide the students. In addition, pdb files of the compounds used in the laboratory are available for the students to download and interactively view, using an appropriate molecular-viewing package such as RasMol.

Laboratory Writeup for Students The laboratory write-up for the students is in Adobe Portable Document format for viewing and Microsoft Word format for downloading and using with the laboratory.

Lecture Notes (Microsoft PowerPoint format)

Instructor's Manual (Adobe Portable Document format) This manual contains information about the length of the experiment, necessary materials, required glassware and equipment, and preparation time.

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Last modified: June 15, 2006