CENTRAL CARBON → GLUTAMATE → ORNITHINE → ARGININE → INDIVIDUAL PATHWAY

Arginine biosynthesis

Follow the carbon skeleton from L-Glutamate to L-Arginine.

What it needs

Glutamate, acetyl-CoA, ATP, reducing power, carbamoyl phosphate and aspartate.

What it supplies

L-Arginine. This product can enter downstream cellular reactions; its synthesis depends on the precursor and helper supplies shown.

The pathway

Read from top to bottom. Select an enzyme box to jump to its reaction. Cosubstrates and selected coproducts appear in the account below.

Open full-resolution vector diagram ↗

Reactions and enzymes

1 · N-Acetylglutamate synthase (ArgA)

L-Glutamate → N-Acetyl-L-glutamate

N-Acetylglutamate synthase (ArgA) · EC 2.3.1.1

Inputs, helpers or coproducts: Acetyl-CoA supplies an acetyl group

2 · Acetylglutamate kinase (ArgB)

N-Acetyl-L-glutamate → N-Acetylglutamyl phosphate

Acetylglutamate kinase (ArgB) · EC 2.7.2.8

Inputs, helpers or coproducts: ATP → ADP

3 · Acetylglutamyl-phosphate reductase (ArgC)

N-Acetylglutamyl phosphate → N-Acetylglutamate semialdehyde

Acetylglutamyl-phosphate reductase (ArgC) · EC 1.2.1.38

Inputs, helpers or coproducts: NADPH supplies reducing power

4 · Acetylornithine aminotransferase (ArgD)

N-Acetylglutamate semialdehyde → N-Acetylornithine

Acetylornithine aminotransferase (ArgD) · EC 2.6.1.11

Inputs, helpers or coproducts: Glutamate supplies the amino group

5 · Acetylornithine deacetylase (ArgE)

N-Acetylornithine → L-Ornithine

Acetylornithine deacetylase (ArgE) · EC 3.5.1.16

Inputs, helpers or coproducts: Acetate released

An acetyl-recycling ArgJ route is an alternative.

6 · Ornithine carbamoyltransferase (ArgF)

L-Ornithine + carbamoyl phosphate → L-Citrulline

Ornithine carbamoyltransferase (ArgF) · EC 2.1.3.3

7 · Argininosuccinate synthase (ArgG)

L-Citrulline + L-aspartate → L-Argininosuccinate

Argininosuccinate synthase (ArgG) · EC 6.3.4.5

Inputs, helpers or coproducts: ATP → AMP + PPᵢ

8 · Argininosuccinate lyase (ArgH)

L-Argininosuccinate → L-Arginine

Argininosuccinate lyase (ArgH) · EC 4.3.2.1

Inputs, helpers or coproducts: Fumarate released

Connected pathways

Glutamate and nitrogen assimilation Proline biosynthesis Aspartate from oxaloacetate

Evidence and scope

This combines a representative acetylated ornithine route (M00028) with the ornithine-to-arginine route (M00844). Acetyl-recycling and other alternatives are not combined into one required sequence. This page explains selected documented biochemical reactions. It does not establish that every displayed enzyme occurs in Aquifex, that the pathway is universally essential, or that the book image records a complete organism. Gene symbols name common enzyme activities; organism-specific protein records require separate matching.

Original explanatory diagram and reaction account, based on the records below. Arrows show the biosynthetic reading direction; they do not claim that every reaction is irreversible. Selected protons, water and cofactors are omitted from the overview and are not implied absent.