Pregled metabolizma proteina

Study Notes

Protein Metabolism Overview

Protein metabolism encompasses the breakdown, synthesis, and utilization of proteins in the body.
Proteins are vital for numerous bodily functions, such as structural support, enzymatic catalysis, and transport.
Protein metabolism involves both catabolic and anabolic processes.
Catabolic processes break down proteins into amino acids.
Anabolic processes synthesize proteins from amino acids.

Protein Breakdown (Catabolism)

Deamination: Removal of the amino group from amino acids.
Transamination: Transfer of the amino group from one amino acid to another.
Oxidative deamination: Amino acids are broken down, releasing nitrogen as ammonia.
Urea cycle: Converts ammonia to urea, a less toxic nitrogenous waste product, for excretion.
Carbon skeletons: The remaining part of the amino acid after deamination, further metabolized into carbohydrate and lipid intermediates.
Fate of the carbon skeletons: Used for energy production, gluconeogenesis, or ketogenesis.

Protein Synthesis (Anabolism)

Amino acid pool: A collection of amino acids circulating in the blood used for protein synthesis.
Genetic code: Dictates the sequence of amino acids in proteins.
Transcription and translation: Cellular processes converting genetic information into proteins.
Protein folding: The process by which a polypeptide chain folds into its three-dimensional structure.
Regulation of protein synthesis: Controlled by hormones, growth factors, and amino acid availability.

Protein Turnover

Continuous process of protein synthesis and degradation.
Crucial for maintaining cellular function and adapting to physiological needs.
Rate of protein turnover differs among tissues and proteins.
Damaged or unneeded proteins are degraded via the ubiquitin-proteasome system.

Amino Acid Classification

Essential amino acids: Cannot be synthesized by the body and must be obtained from the diet.
Non-essential amino acids: Can be synthesized by the body.
Conditional amino acids: Non-essential, but become essential under specific conditions (like illness or stress).

Protein Digestion

Proteins are initially broken down into smaller polypeptides by enzymes in the stomach and small intestine.
Peptidases: Enzymes hydrolysing peptide bonds to release individual amino acids.
Absorption of amino acids occurs in the small intestine.

Protein Metabolism Disorders

Phenylketonuria (PKU): A genetic disorder affecting phenylalanine metabolism, causing phenylalanine buildup in the blood.
Maple syrup urine disease (MSUD): A genetic disorder affecting branched-chain amino acid metabolism, leading to branched-chain amino acid accumulation.
Other inherited metabolic disorders: Numerous inherited disorders can affect specific steps in protein metabolism, causing varied symptoms.

Hormonal Regulation

Hormones impact protein metabolism through various mechanisms influencing synthesis, breakdown, and amino acid utilization.
Insulin: Promotes protein synthesis and inhibits degradation.
Glucagon: Stimulates protein degradation and gluconeogenesis.
Growth hormone: Influences protein synthesis and growth.
Cortisol: Affects both protein breakdown and synthesis depending on conditions.

Importance of Adequate Protein Intake

Crucial for tissue growth, repair, and maintenance.
Contributes to immune function, enzyme activity, and hormone production.
Necessary for various bodily functions.

Special Considerations

Nitrogen balance: Measures nitrogen intake versus excretion, reflecting protein status.
Positive nitrogen balance: Synthesis exceeds degradation.
Negative nitrogen balance: Degradation exceeds synthesis.
Protein requirements vary by age, activity level, and health conditions.

Description

Ovaj kviz istražuje prostore razgradnje i sinteze proteina u tijelu. Upoznajte se s kataboličkim i anaboličkim procesima, uključujući deaminaciju i ureu. Otkrijte kako proteini igraju ključnu ulogu u raznim tjelesnim funkcijama.