Chemistry of Signalling Metals

What role do metals play in biology?

Metals are crucial for transcription, translation, signaling, transport, and catalysis.

Which ions are key in neuronal signaling?

Sodium (Na+), Potassium (K+), and Calcium (Ca2+).

What maintains the resting membrane potential?

High Na+ outside and high K+ inside the cell.

Role of calcium in fertilization?

Triggers repetitive Ca2+ oscillations to activate the egg after sperm entry.

Role of calcium during mitosis?

A transient rise in Ca2+ at metaphase-anaphase transition facilitates cell division.

Why is magnesium essential?

Acts as a cofactor for over 300 enzymes including those in ATP/DNA/RNA metabolism.

What happens in magnesium deficiency?

Muscle spasms, cardiovascular issues, diabetes, high blood pressure, migraines.

How does magnesium impact insulin action?

Low intracellular Mg2+ impairs insulin receptor function and promotes insulin resistance.

Role of magnesium in glycolysis?

Stabilizes phosphate groups and activates glycolytic enzymes.

Role of magnesium in nucleic acids?

Neutralizes negative charges on DNA/RNA to stabilize their structures.

Function of manganese in organisms?

Acts as cofactor for detoxifying enzymes and supports metabolic processes.

Toxic effect of excess manganese?

Causes manganism, a neurodegenerative condition similar to Parkinson's.

Enzymes that use manganese?

Arginase and manganese-containing superoxide dismutase (Mn-SOD).

Function of arginase?

Catalyzes the conversion of arginine to urea and ornithine in the urea cycle.

Function of superoxide dismutase (SOD)?

Dismutates superoxide radicals into oxygen and hydrogen peroxide.

Types of SOD based on metal cofactors?

Copper-Zinc SOD (cytosol) and Manganese SOD (mitochondria).

What harmful molecule does SOD regulate?

Superoxide radical (O2−).

What enzymes degrade hydrogen peroxide after SOD activity?

Catalase.

Effect of thiazolidinediones on magnesium?

Increase intracellular magnesium, improving insulin sensitivity.

Where are manganese SOD enzymes primarily found?

In mitochondria.