glycine metabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways involving glycine, aminoethanoic acid. [GOC:go_curators]

Glycine metabolism is a complex and vital biological process involving the synthesis, breakdown, and utilization of glycine. Glycine, the simplest amino acid, plays a crucial role in various cellular functions, including protein synthesis, collagen formation, detoxification, and neurotransmission.

**Glycine Synthesis:**
- Glycine is primarily synthesized from serine via the enzyme serine hydroxymethyltransferase (SHMT), which catalyzes the transfer of a one-carbon unit from tetrahydrofolate to serine.
- Glycine can also be synthesized from glyoxylate, a precursor of the glyoxylate cycle, through the action of glyoxylate reductase.

**Glycine Breakdown:**
- Glycine breakdown primarily occurs through the glycine cleavage system, a multi-enzyme complex that converts glycine to carbon dioxide, ammonia, and methylenetetrahydrofolate.
- This process is catalyzed by the following enzymes: glycine decarboxylase (GLDC), aminomethyltransferase (AMT), and tetrahydrofolate reductase (THF reductase).

**Glycine Utilization:**
- Glycine serves as a building block for proteins and peptides, including collagen, elastin, and glutathione.
- It is involved in the biosynthesis of purines and porphyrins, essential components of DNA and heme, respectively.
- Glycine acts as a neurotransmitter in the central nervous system, mediating inhibitory signals.
- It plays a role in detoxification, particularly in the breakdown of toxic substances like formaldehyde.

**Regulation of Glycine Metabolism:**
- The activity of enzymes involved in glycine metabolism, such as SHMT and GLDC, is tightly regulated by factors like substrate availability, cofactor levels, and metabolic demands.
- Hormones like insulin and glucagon can also influence glycine metabolism by altering enzyme activity.

**Clinical Significance:**
- Defects in glycine metabolism can lead to various disorders, such as nonketotic hyperglycinemia, a severe neurological disorder characterized by high levels of glycine in the blood.
- Glycine deficiency can also occur, potentially leading to impaired protein synthesis and collagen production.

In summary, glycine metabolism is a fundamental process involving synthesis, breakdown, and utilization of this crucial amino acid. Its intricate pathways are essential for various cellular functions, and disruptions in glycine metabolism can have significant clinical implications.'
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Proteins (4)

Compounds (14)