11.1: Bioinorganic Chemistry

Introduction to Bioinorganic Chemistry

What is bioinorganic chemistry? To answer this question, we should probably define what the other fields of chemistry are first...

You probably know that "biochemistry" is the study of the chemistry of biology - or life. The term "organic chemistry" literally means the chemistry of life. Organic chemistry is the study of carbon-based molecules because the first molecules that were isolated from living organisms contained carbon. On the other hand, the first minerals and other non-living things seemed to be made of other elements. For quite some time scientists naively assumed that all living things were made of carbon-based molecules, while non-living things did not contain carbon. "Organic chemistry" was the study of the carbon-based molecules of life, while "inorganic chemistry" was the study of  "non-living" and "non-carbon" molecules.

Do these these historic definitions still hold true? To answer that question, let's look at one of the most important reactions in your life, shown below.

\[O_2 + 4e^- + 4H^+ \rightleftharpoons H_2O\]

Is this reaction carbon-based? Is it living? Well, take a deep breath! When you breath, you inhale mostly nitrogen gas (N₂), but also some oxygen gas (O₂). The oxygen gas that you inhale is critical for energy production in every one of your cells. During aerobic metabolism, O₂ accepts 4 electrons and 4 hydrogen ions to become two molecules of water. This reaction provides the driving force for phosphorylation of ATP that is required to fuel countless other essential reactions that keep you alive. This reaction is responsible for all aerobic life. And, it's inorganic! This simple example shows how the historic names of organic and inorganic chemistry should not be taken literally. 

There are additional inorganic components required for this reaction too! For example, most of the proteins of the electron transport chain (the proteins that catalyze reduction of oxygen in the mitochondria of your cells) require metal cofactors and metal active sites. Please watch the video below to see some examples. Articles about the individual proteins from the video are provided below.

Links to articles about proteins discussed in this video:

• Cytochrome C Oxidase
• Ribozyme (has not been written yet!)
• Hemocyanin (has not been written yet!)
• Urease (has not been written yet!)

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Sources

1. Franz, Katherine J., The Periodic Table of Life, Core Concepts in Chemistry, a free course on iTunes U from Duke University.

• 11.1.1: A Molecular Depot- Human Serum Albumin Carries Essential Cu and Zn in Serum

  Human serum albumin (HSA) is the most abundant protein in human blood and cerebral spinal fluid. Among its many functions, HSA carries essential Cu and Zn ions in human serum. This is a description of its Cu and Zn coordination chemistry.

• 11.1.2: Iron acquisition in bacteria- Siderophores

  This is a description of the the small molecules produced by bacteria to acquire essential iron from their environment. This page was originally contributed by Emma Bridgman, and undergraduate student at Saint Mary's College in Notre Dame, IN.

• 11.1.3: Fe Wars- Lactoferrin

• 11.1.4: Iron Storage- Ferritin

• 11.1.5: Antioxidant- Cu/Zn Superoxide dismutase (SOD1)

  This is a description of the cytoplasmic antioxidant enzyme, Cu,Zn-Superoxide Dismutase (SOD1), which catalyzes the disproportionation of superoxide. This page was originally contributed by Margaret Mraz, an undergraduate student at Saint Mary's College in Notre Dame, IN.

• 11.1.6: Keep Cu Safe- Intracellular Copper Chaperones

  This is a description of the yeast cytoplasmic copper chaperone Atx1. This copper chaperone is highly conserved among eukaryotic species, including human. Copper chaperones transport and protect essential copper from its entry point at the plasma membrane to its target proteins throughout the cell. This page and all images are original contributions by Adrienne Bruggeman, an undergraduate student at Saint Mary's College in Notre Dame, IN.

• 11.1.7: Cytochrome C

• 11.1.8: Cytochrome Oxidase

• 11.1.9: Potassium Channels

  Ion channels are large membrane-spanning proteins that allow selective transport of an ion. This can occur for ions like potassium, calcium, and sodium. These channels are responsible for the electrical conduction in nervous systems to allow nerve and muscle cells to function properly. Neuron plasma membranes contain ion channels that have the ability to open and close based on these electric signals received from neuron activity.

• 11.1.10: Chemotherapy- Pt anticancer agents

  This is a description of Platinum Chemotherapy agents. The most notable of this class of drugs is cisplatin, which was one of the first and is the most effective chemotherapy drug to treat several types of cancer.