Problem 12 - Clinical Chemistry

Question

The metal ion essential for the activity of xanthine oxidase and xanthine dehydrogenase is a. Molybdenum b. Iron c. Zinc d. Manganese

Step-by-Step Solution

Answer

a. Molybdenum

Step 1: Understand the Enzyme Function

Know that xanthine oxidase and xanthine dehydrogenase are enzymes involved in the metabolic breakdown of purines in the body, producing uric acid.

Step 2: Identify Common Metal Ions in Enzymes

Recognize that certain metal ions, such as Molybdenum, Iron, Zinc, and Manganese, are common cofactors required for enzyme activity.

Step 3: Determine the Specific Metal Ion

From biochemical knowledge, identify that molybdenum is the metal ion crucial for the proper function of xanthine oxidase and xanthine dehydrogenase.

Key Concepts

enzyme function

Xanthine oxidase and xanthine dehydrogenase are important enzymes in the body.
They play key roles in the metabolic breakdown of purines which are components of DNA and RNA.
This breakdown leads to the production of uric acid, which is then expelled from the body.
Enzymes like xanthine oxidase and xanthine dehydrogenase facilitate these chemical reactions by lowering the energy required for the reactions to occur.

• Enzymes speed up biochemical reactions in the body.
• They work by binding to substrates, which are the molecules upon which enzymes act.
• By binding to substrates, enzymes allow reactions to proceed faster and more efficiently.

Without these enzymes, the breakdown of purines would be much slower or might not happen at all.
This would cause an accumulation of purines in the body and could lead to serious health issues.

metal ion cofactors

Metal ion cofactors are essential for the proper functioning of many enzymes.
These cofactors are non-protein chemical compounds that bind to enzymes and assist in catalyzing reactions.

• Molybdenum, Iron, Zinc, and Manganese are common metal ion cofactors.
• These metal ions help in stabilizing enzyme structure and participate in the catalytic process.
• The absence of appropriate metal ions can hinder enzyme activity.

In the case of xanthine oxidase and xanthine dehydrogenase, molybdenum is the crucial metal ion.
This is because molybdenum provides the proper electrochemical environment necessary for these enzymes to catalyze the oxidation of xanthine, producing uric acid.

molybdenum in biochemical reactions

Molybdenum is essential in various biochemical reactions in the body.
It acts as a cofactor for several important enzymes apart from xanthine oxidase and xanthine dehydrogenase.
These enzymes play crucial roles in detoxifying substances and catalyzing various metabolic reactions.

• Molybdenum-dependent enzymes are vital for the metabolism of sulfur-containing amino acids.
• They help in the detoxification of harmful substances through processes called hydroxylation.
• Due to its versatile oxidation states, molybdenum can transfer electrons during chemical reactions, facilitating these reactions.

This metal ion is also involved in the nitrogen cycle, which is essential for the synthesis of amino acids and nucleic acids.
Thus, molybdenum is a key player in multiple biochemical pathways in living organisms.