Síntesis y estructura del colágeno [PASO A PASO].

Metabolism of Collagen

In this section, the speaker discusses the metabolism of collagen, focusing on its molecular structure and the essential steps for its proper formation. The importance of collagen in the body is highlighted.

Types and Distribution of Collagen

• Collagen is a crucial protein constituting about 25% of total body proteins, providing support to connective tissues like skin, ligaments, blood vessels, corneas, cartilage, tendons, and bones.

• There are various types of collagen classified based on their molecular and three-dimensional structures. To date, 28 types have been discovered with common types being 1, 2, 3, 4, and 5.

Structure of Collagen

• All collagen types share a trimeric structure composed of three polypeptides called alpha chains. These chains can be identical (homotrimer) or different (heterotrimer).

• Each alpha chain consists of repetitive amino acid sequences in trios such as glycine-proline-X or glycine-X-hydroxyproline. Glycine is the most common amino acid in these chains.

Synthesis Process

• Fibroblasts are specialized cells responsible for collagen synthesis. The process starts with transcription of genes encoding alpha chains in the fibroblast nucleus.

• Post-translational modifications occur in the endoplasmic reticulum involving removal of signal peptides and hydroxylation of proline and lysine residues by prolyl hydroxylase and lysyl hydroxylase enzymes.

• Vitamin C and iron play crucial roles in these modifications. Deficiencies can lead to assembly issues during collagen formation.

Continuation: Synthesis Process

This section delves deeper into post-translational modifications required for proper collagen synthesis.

Further Modifications

• Glucosylation involves adding sugars like glucose and galactose to specific sites on procollagen after prior hydroxylation by prolyl hydroxylase and lysyl hydroxylase enzymes.

• Procollagen assembly occurs in Golgi apparatus where it is packaged into vesicles for extracellular transport via secretory pathways.

Protein Metabolism Process

In this section, the process of collagen metabolism is discussed, focusing on the role of enzymes in cutting protruding ends and forming collagen tropocollagen with the help of lysyl hydroxylase.

Collagen Formation Process

• Enzymes called peptidases cut protruding ends of collagen with tropocollagen formation.

• Tropocollagens are joined by covalent bonds through a process known as cross-linking.

• Cross-linking allows for the formation of collagen fibrils, which then form larger structures like collagen fibers.

Factors Affecting Collagen Structure

This section delves into factors influencing collagen structure, such as location within the body and type variations impacting lifespan and degradation processes.

Influencing Factors on Collagen

• The lifespan of collagen fibers varies from months to years based on location and type; for instance, intervertebral disc collagen can last up to approximately 117 years.

• Enzymes play a crucial role in collagen degradation; alterations in these enzymes can lead to rapid breakdown, affecting extracellular matrix metabolism.

• Mutations in genes encoding collagen chains or enzymes involved in collagen formation can disrupt metabolism processes.

Importance of Collagen in Health

This part emphasizes the significance of collagen in maintaining tissue health and discusses how metabolic failures related to collagen can lead to various health issues.

Role of Collagen in Health

• Collagen's diverse functions make it a key protein in tissues; metabolic failures can result in mild to severe illnesses.

• Consumption of edible animal sources containing collagen does not directly translate into intact skin or bone benefits; digestion breaks down collagen into amino acids for cellular use.