Biochemistry

Glutathione

• Structure: A tripeptide made of Glutamate, Cysteine, and Glycine (linked as Glutamyl-Cysteinyl-Glycine).

• Function:

  • Major antioxidant in cells—neutralizes reactive oxygen species (ROS).

  • Involved in detoxification, immune function, and redox signaling.

• Fun Fact: Exists in reduced (GSH) and oxidized (GSSG) forms—its ratio is a marker of oxidative stress.

 Creatinine

• Synthesis: Derived from Glycine, Arginine, and Methionine via creatine metabolism.

• Function:

  • Waste product of muscle metabolism.

  • Excreted by kidneys—used as a marker of renal function in blood tests.

• Clinical Insight: Elevated serum creatinine often signals impaired kidney function.

Calcium-Binding Proteins

1. Troponin-C

• Role: Part of the troponin complex in skeletal and cardiac muscle.

• Function: Binds calcium to initiate muscle contraction by enabling actin-myosin interaction.

• Clinical Use: Troponin levels are measured to diagnose myocardial infarction.

2. Calmodulin

• Structure: Small, highly conserved protein with 4 calcium-binding sites.

• Function:

  • Acts as a calcium sensor and regulator.

  • Modulates activity of enzymes, ion channels, and other proteins in response to calcium levels.

• Versatility: Involved in smooth muscle contraction, metabolism, memory formation, and more.