ALS

Gene Description

Acetolactate synthase, a thiamine-diphosphate- and magnesium-dependent enzyme catalyzing the first committed steps toward branched-chain amino acid biosynthesis.

Core Functions

Catalyzes pyruvate condensation to acetolactate as part of branched-chain amino acid biosynthesis.

Molecular Function:

acetolactate synthase activity

Directly Involved In:

L-isoleucine biosynthetic process L-valine biosynthetic process

Cellular Locations:

chloroplast stroma

In Complex:

acetolactate synthase complex

Supporting Evidence:

file:MISSI/ALS/ALS-uniprot.txt
Reaction=2 pyruvate + H(+) = (2S)-2-acetolactate + CO2
file:MISSI/ALS/ALS-uniprot.txt
PATHWAY: Amino-acid biosynthesis; L-isoleucine biosynthesis; L-isoleucine from 2-oxobutanoate: step 1/4.
file:MISSI/ALS/ALS-uniprot.txt
COFACTOR: Name=thiamine diphosphate
file:interpro/panther/PTHR18968/PTHR18968-entries.csv
Q41768,"Acetolactate synthase 1, chloroplastic",protein,4577,Zea mays
file:interpro/panther/PTHR18968/PTHR18968-entries.csv
P17597,"Acetolactate synthase, chloroplastic",protein,3702,Arabidopsis thaliana

References

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Suggested Experiments

Experiment: Assay ALS activity and herbicide inhibition in vitro using Miscanthus enzyme variants.

Type: targeted functional assay

📚 Additional Documentation

Notes

(ALS-notes.md)

Curation notes

QuickGO export is header-only; therefore no UniProt DR/InterPro-derived terms are listed as existing_annotations or proposed as NEW.
Core function focuses on acetolactate synthase activity in branched-chain amino acid biosynthesis; herbicide response is not treated as a core function.
Added chloroplast stroma localization after PR re-review. UniProt lacks a direct location line for this Miscanthus entry, but plant ALS homologs in PTHR18968 include chloroplastic Arabidopsis and maize enzymes; the PANTHER subfamily label says mitochondrial and is not used for localization.