Amino Acid Pool Regulation

Amino Acid Pool and Protein Turnover

• Amino pool depleted via synthesis of body proteins, amino acids used for nitrogen-containing compounds, and conversion to glucose or fatty acids.
• The amino acid pool is approximately 90-100 grams, contrasting with around 12 kg of total body protein in a 70-kg individual.
• Protein turnover involves continual synthesis and degradation of proteins to remove unwanted ones.
• For some proteins, synthesis regulation is crucial, while others depend on selective degradation for maintaining levels.

Plasma Proteins

• Plasma proteins, synthesized mainly by the liver, perform various biological roles.
• Key plasma proteins: albumin (60% of plasma proteins), globulins (including alpha, beta, and gamma globulins), and fibrinogen.

Functions of Plasma Proteins

• Albumin: Maintains blood osmotic pressure and electrolyte balance.
• Globulins: Transport hormones and nutrients; includes immunoglobulins for immune response.
• Fibrinogen: Essential for blood clotting, converting into fibrin during the clotting process.

Hormonal Regulation of Protein Metabolism

• Proteins undergo catabolism to replenish the intracellular amino acid pool, facilitated by proteases.
• Muscle proteins can degrade to amino acids for energy in starvation; glutamine provides fuel during metabolic acidosis.
• Excess amino acids are converted to glucose or ketones; decomposition produces waste products.
• Urea cycle processes and excretes nitrogen to prevent toxicity from high ammonium ion levels.

Vitamins

• Essential vitamins (13 total) are derived from diet; divided into water-soluble and fat-soluble groups.
• Cannot be sufficiently synthesized by the body, necessitating dietary intake.

Water-Soluble Vitamins

• Vitamin B1 (Thiamin): Nerve function, carbohydrate metabolism; deficiency leads to nervous and cardiac issues.
• Vitamin B2 (Riboflavin): Energy production and skin health; deficiency causes skin and ocular symptoms.
• Niacin: Supports metabolism and skin health; deficiency results in skin lesions and gastrointestinal issues.
• Vitamin B6: Aids in amino acid metabolism and hemoglobin synthesis; deficiency linked to dermatitis and mental health issues.
• Folic Acid (B9): Essential for DNA synthesis and red blood cell maturation; deficiency can cause anemia and neural tube defects.
• Vitamin B12: Required for amino acid and cell metabolism; deficiency leads to tongue smoothness and gastrointestinal disturbances.
• Pantothenic Acid: Involved in macronutrient metabolism; deficiency causes fatigue and gastrointestinal issues.
• Biotin: Important for metabolism of macronutrients; deficiency may cause dermatitis and hair loss.
• Vitamin C: Antioxidant and collagen synthesis; deficiency leads to scurvy and immune issues.

Fat-Soluble Vitamins

• Vitamin A: Vital for vision, skin health, and immunity; deficiency causes vision problems and skin issues.
• Vitamin D: Regulates calcium and bone health; deficiency leads to soft bones and growth issues.
• Vitamin E: Antioxidant protecting cells; deficiency can cause nerve issues and red blood cell breakdown.
• Vitamin K: Essential for blood coagulation and bone health; deficiency may result in bleeding disorders.

Importance of Vitamins in Health

• Vitamins play critical roles in maintaining overall health, with varied functions that impact metabolism, immune response, and cellular processes.
• Supplementation trends show increasing importance, especially for vitamins like B6, B12, C, D, E, and K.