glucuronate catabolic process to xylulose 5-phosphate

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the breakdown of glucuronate into other compounds, including xylulose 5-phosphate. [GOC:go_curators]

The glucuronate catabolic process to xylulose 5-phosphate is a multi-step metabolic pathway that involves the conversion of glucuronic acid to xylulose 5-phosphate. This pathway is crucial for the detoxification of various compounds, including steroid hormones, bilirubin, and drugs.

**Step 1: Glucuronic acid to D-glucuronate**
Glucuronic acid, a derivative of glucose, is first reduced to D-glucuronate by the enzyme glucuronate reductase. This reduction step utilizes NADPH as a reducing agent.

**Step 2: D-glucuronate to L-gulonate**
D-glucuronate is then epimerized to L-gulonate by the enzyme D-glucuronate 3-epimerase. This epimerization involves the inversion of the configuration at the C-3 carbon atom.

**Step 3: L-gulonate to L-xylulose**
L-gulonate is oxidized to L-xylulose by the enzyme L-gulonate dehydrogenase. This oxidation step utilizes NAD+ as an oxidizing agent.

**Step 4: L-xylulose to D-xylulose**
L-xylulose is then epimerized to D-xylulose by the enzyme L-xylulose 5-epimerase. This epimerization involves the inversion of the configuration at the C-5 carbon atom.

**Step 5: D-xylulose to xylulose 5-phosphate**
Finally, D-xylulose is phosphorylated to xylulose 5-phosphate by the enzyme xylulose kinase. This phosphorylation step utilizes ATP as a phosphate donor.

**Overall reaction:**

Glucuronic acid + NADPH + NAD+ + ATP → xylulose 5-phosphate + NADP+ + ADP + H2O

**Regulation:**

The glucuronate catabolic process is tightly regulated by various factors, including substrate availability, enzyme activity, and hormonal signals.

**Clinical significance:**

Deficiencies in enzymes involved in this pathway can lead to various metabolic disorders, such as pentosuria and glucuronic aciduria. Moreover, this pathway is important for the detoxification of xenobiotics, and disruptions in its function can contribute to drug toxicity.

**Summary:**

The glucuronate catabolic process to xylulose 5-phosphate is a vital metabolic pathway that plays crucial roles in detoxification, carbohydrate metabolism, and cellular signaling. The pathway involves a series of enzymatic steps that convert glucuronic acid to xylulose 5-phosphate, a key intermediate in the pentose phosphate pathway.'
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Proteins (3)

Compounds (25)