N-acetylneuraminate catabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the breakdown of N-acetylneuraminate, the anion of 5-(acetylamino)-3,5-dideoxy-D-glycero-D-galacto-non-3-ulosonic acid. [ISBN:0198506732]

N-acetylneuraminate catabolism is a crucial biological process that involves the breakdown of N-acetylneuraminic acid (Neu5Ac), a common sialic acid found in various biomolecules like glycoproteins and glycolipids. This process plays a vital role in cellular functions, including cell signaling, immune responses, and development.

The catabolism of Neu5Ac primarily occurs in lysosomes, specialized organelles responsible for degrading cellular waste. The process is initiated by the enzyme neuraminidase, also known as sialidase, which cleaves the terminal Neu5Ac residue from glycoconjugates.

Once cleaved, Neu5Ac undergoes a series of enzymatic reactions. The first step involves the conversion of Neu5Ac to N-acetylmannosamine (ManNAc) by the enzyme N-acetylneuraminate lyase. ManNAc is then further metabolized via the hexosamine biosynthesis pathway, a central metabolic route responsible for the synthesis of UDP-N-acetylglucosamine (UDP-GlcNAc), a precursor for various biomolecules including glycosaminoglycans and glycoproteins.

The catabolism of Neu5Ac can also occur in the cytosol, where it is processed by the enzyme CMP-sialic acid synthetase to produce CMP-Neu5Ac, a key intermediate in the biosynthesis of sialylated glycoconjugates. This pathway allows for the recycling of Neu5Ac and its utilization for the synthesis of new sialylated molecules.

Defects in N-acetylneuraminate catabolism can lead to various diseases. For example, deficiencies in neuraminidase activity can cause sialidosis, a lysosomal storage disorder characterized by an accumulation of sialylated glycoproteins in various tissues. Similarly, mutations in the N-acetylneuraminate lyase gene can cause sialuria, a metabolic disorder associated with elevated levels of Neu5Ac in urine.

In summary, N-acetylneuraminate catabolism is a complex and essential biological process that involves the breakdown of Neu5Ac and its conversion to various metabolic intermediates. This process is crucial for cellular functions and its disruption can lead to a range of diseases.'
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Proteins (1)

Compounds (2)