Protein Synthesis Process

Protein Synthesis

• Process by which cells create proteins
• Occurs in ribosomes, involving mRNA, tRNA, and amino acids
• Steps:
  1. Transcription: DNA sequence is transcribed into mRNA
  2. Translation: mRNA sequence is translated into amino acid sequence
  3. Initiation: Ribosome binds to mRNA, initiating protein synthesis
  4. Elongation: Amino acids are added to growing protein chain
  5. Termination: Protein synthesis is completed, and protein is released

Amino Acid Degradation

• Process by which cells break down amino acids
• Occurs in liver and kidneys, and involves deamination and transamination
• Steps:
  1. Deamination: Amino group is removed from amino acid, converting it to an alpha-keto acid
  2. Transamination: Alpha-keto acid is converted to another alpha-keto acid, which can be used in energy production or gluconeogenesis
  3. Oxidative Decarboxylation: Alpha-keto acid is converted to acetyl-CoA, which enters the citric acid cycle

Transamination

• Reaction in which an amino acid is converted to an alpha-keto acid
• Catalyzed by transaminases, which require pyridoxal phosphate (PLP) as a coenzyme
• Reversible reaction: Alpha-amino acid + Alpha-keto acid ⇌ Alpha-keto acid + Alpha-amino acid

Deamination

• Reaction in which an amino group is removed from an amino acid
• Catalyzed by enzymes such as glutamate dehydrogenase and amino acid oxidases
• Results in the formation of an alpha-keto acid and ammonia (NH3)

Urea Cycle (Ureagenesis)

• Process by which ammonia (NH3) is converted to urea, which is excreted in urine
• Occurs in liver, and involves the following steps:
  1. Citrulline synthesis: Ornithine and carbamoyl phosphate react to form citrulline
  2. Argininosuccinate synthesis: Citrulline and aspartate react to form argininosuccinate
  3. Arginine synthesis: Argininosuccinate is cleaved to form arginine and fumarate
  4. Urea synthesis: Arginine is hydrolyzed to form urea and ornithine

Protein Synthesis

• Process by which cells create proteins
• Occurs in ribosomes, involving mRNA, tRNA, and amino acids

Transcription

• DNA sequence is transcribed into mRNA

Translation

• mRNA sequence is translated into amino acid sequence

Initiation

• Ribosome binds to mRNA, initiating protein synthesis

Elongation

• Amino acids are added to growing protein chain

Termination

• Protein synthesis is completed, and protein is released

Amino Acid Degradation

• Process by which cells break down amino acids
• Occurs in liver and kidneys

Deamination

• Amino group is removed from amino acid, converting it to an alpha-keto acid

Transamination

• Alpha-keto acid is converted to another alpha-keto acid

Oxidative Decarboxylation

• Alpha-keto acid is converted to acetyl-CoA, which enters the citric acid cycle

Transamination

• Reaction in which an amino acid is converted to an alpha-keto acid
• Catalyzed by transaminases, which require pyridoxal phosphate (PLP) as a coenzyme
• Reversible reaction: Alpha-amino acid + Alpha-keto acid ⇌ Alpha-keto acid + Alpha-amino acid

Deamination

• Reaction in which an amino group is removed from an amino acid
• Catalyzed by enzymes such as glutamate dehydrogenase and amino acid oxidases
• Results in the formation of an alpha-keto acid and ammonia (NH3)

Urea Cycle (Ureagenesis)

• Process by which ammonia (NH3) is converted to urea, which is excreted in urine
• Occurs in liver

Citrulline Synthesis

• Ornithine and carbamoyl phosphate react to form citrulline

Argininosuccinate Synthesis

• Citrulline and aspartate react to form argininosuccinate

Arginine Synthesis

• Argininosuccinate is cleaved to form arginine and fumarate

Urea Synthesis

• Arginine is hydrolyzed to form urea and ornithine