Amino Acid Metabolism & Urea Cycle

A cycle transporting excess nitrogen from muscle to liver, converting it to glucose for export back to muscles.

The removal of an amino group from an amino acid, generating a carbon skeleton and ammonium.

An amino acid that transports nitrogen to the liver in the Glucose-Alanine cycle.

Amino acid that acts as an ammonia acceptor (in AA degradation) and donor (for biosynthesis/excretion).

An amino acid, a key transporter of amino groups between tissues and the liver, and a higher level in blood versus other amino acids.

Precursor for gluconeogenesis formed during Alanine deamination.

The part of an amino acid remaining after deamination.

Alanine, Aspartate, Glutamate, and Glutamine are key players in transporting/removing nitrogen.

Amino acids are small molecules with a carbon skeleton and an amine group (-NH2).

Amino acids have multiple roles, including building proteins, creating other molecules, and acting as fuel.

Essential amino acids are obtained through diet, while non-essential amino acids are made by the body.

Amino acids that can be converted to glucose or ketone bodies.

The process of creating amino acids within the body.

Amino acid metabolism connects with the main metabolic pathways, like the TCA cycle.

The breakdown of amino acids.

The process of removing nitrogen from amino acids to form carbon skeletons.

The urea cycle converts ammonia into urea to remove nitrogen.

A B vitamin important in amino acid metabolism.

Amino acids that the body cannot synthesize and must be obtained from the diet.

Amino acids that the body can synthesize from other compounds.

Amino acids whose carbon skeletons can be converted to glucose.

Amino acids whose carbon skeletons can be converted into ketone bodies.

The removal of an amino group from an amino acid.

A process in the liver that converts toxic ammonia to less harmful urea, which is excreted.

The breakdown and synthesis of amino acids in the body.

A metabolic pathway where amino acid carbon skeletons can enter for energy production.

The production of glucose from non-carbohydrate sources, such as amino acids.

Enzymes that catalyze the transfer of an amino group from one molecule to another.

Glutamate Dehydrogenase is an enzyme involved in oxidative deamination of glutamate, removing its amino group and producing α-ketoglutarate, NADH, H+ and ammonium. This process is crucial for ammonia metabolism.

The ammonium produced during deamination is used to form urea, which is a less toxic form of nitrogen that can be excreted by the body.

Hyperammonaemia refers to an elevated ammonia level in the blood, a potentially dangerous condition as ammonia readily crosses the blood-brain barrier by diffusion.

Excess ammonia can lead to several toxic effects, including: increased levels of glutamate (excitotoxin), activation of NMDA receptors, elevated glutamine, depletion of ATP, and brain swelling.

The urea cycle is a metabolic process that minimizes the risk of excess ammonia in the body by converting ammonia into urea for excretion.

When we eat more protein than our body needs, it's not stored as protein. Instead, it's broken down into amino acids and used for energy or converted to fat.

Excess amino acids are broken down into their carbon skeletons and amino groups. The carbon skeletons are used for energy or stored as fat, while the amino groups are converted to urea for excretion.

The R group, or side chain, gives each amino acid its unique properties. This variation allows for a wide range of protein structures and functions.

At physiological pH, amino groups are positively charged (NH3+) and carboxyl groups are negatively charged (COO-).

Metabolically, amino acids are considered as a carbon skeleton (alpha keto acid) and an amino group. The carbon skeleton can be recycled for energy or biosynthesis.

Free ammonia is toxic and can cause brain swelling, coma, and death. Careful handling of the amino groups is important during amino acid metabolism.

Amino acids can be classified by their side chain properties, metabolic fate (glucogenic/ketogenic), and dietary availability (essential/non-essential). This classification helps understand their specific roles in the body.