LEU1/YGL009C Summary Help

Standard Name LEU1 1
Systematic Name YGL009C
Feature Type ORF, Verified
Description Isopropylmalate isomerase; catalyzes the second step in the leucine biosynthesis pathway (1, 2 and see Summary Paragraph)
Name Description LEUcine biosynthesis 1
Chromosomal Location
ChrVII:478652 to 476313 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: -5 cM
Gene Ontology Annotations All LEU1 GO evidence and references
  View Computational GO annotations for LEU1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 14 genes
Classical genetics
Large-scale survey
69 total interaction(s) for 56 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 23
  • Affinity Capture-RNA: 4
  • PCA: 2

Genetic Interactions
  • Negative Genetic: 32
  • Phenotypic Suppression: 2
  • Positive Genetic: 6

Expression Summary
Length (a.a.) 779
Molecular Weight (Da) 85,794
Isoelectric Point (pI) 5.74
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrVII:478652 to 476313 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Genetic position: -5 cM
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..2340 478652..476313 2011-02-03 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000002977

LEU1 encodes isopropylmalate isomerase (isopropylmalate dehydratase), which catalyzes the conversion of alpha-isopropylmalate into beta-isopropylmalate in the second step of leucine biosynthesis (see pathway diagram) (3 and reviewed in 4). Leu1p is an iron-sulfur (Fe-S) protein that is very sensitive to degradation when removed from intact cells but can be stabilized by high glycerol or high ionic concentrations, conditions which also inactivate the enzyme (5). In contrast to most of the enzymes involved in the superpathway of branched-chain amino acid (valine, leucine, isoleucine) biosynthesis, which are mitochondrial, Leu1p localizes to the cytoplasm (6).

Like the other genes in the leucine biosynthesis pathway, LEU1 is transcriptionally repressed in the presence of leucine (7, 1). LEU1 expression is induced by the transcriptional regulator Leu3p bound to the leucine precursor alpha-isopropylmalate, which recognizes an upstream activation signal in the LEU1 promoter (8, 9). LEU1 transcription has also been shown to be upregulated by the transcriptional activator Gcn4p (10).

leu1 null mutations result in leucine auxotrophy (1), as do mutations affecting gene products that contribute to the incorporation or stability of the Leu1p Fe-S cluster, such as Atm1p and Sod1p (11 and reviewed in 4).

Last updated: 2006-08-08 Contact SGD

References cited on this page View Complete Literature Guide for LEU1
1) Hsu YP and Schimmel P  (1984) Yeast LEU1. Repression of mRNA levels by leucine and relationship of 5'-noncoding region to that of LEU2. J Biol Chem 259(6):3714-9
2) Skala J, et al.  (1991) Complete sequence of the Saccharomyces cerevisiae LEU1 gene encoding isopropylmalate isomerase. Yeast 7(3):281-5
3) Kohlhaw GB  (1988) Isopropylmalate dehydratase from yeast. Methods Enzymol 166:423-9
4) Kohlhaw GB  (2003) Leucine biosynthesis in fungi: entering metabolism through the back door. Microbiol Mol Biol Rev 67(1):1-15, table of contents
5) Bigelis R and Umbarger HE  (1976) Yeast alpha-isopropylmalate isomerase. Factors affecting stability and enzyme activity. J Biol Chem 251(12):3545-52
6) Ryan ED, et al.  (1973) Subcellular localization of the leucine biosynthetic enzymes in yeast. J Bacteriol 116(1):222-5
7) Satyanarayana T, et al.  (1968) Biosynthesis of branched-chain amino acids in yeast: regulation of leucine biosynthesis in prototrophic and leucine auxotrophic strains. J Bacteriol 96(6):2018-24
8) Friden P and Schimmel P  (1987) LEU3 of Saccharomyces cerevisiae encodes a factor for control of RNA levels of a group of leucine-specific genes. Mol Cell Biol 7(8):2708-17
9) Baichwal VR, et al.  (1983) Leucine biosynthesis in yeast : Identification of two genes (LEU4, LEU5) that affect alpha-Isopropylmalate synthase activity and evidence that LEU1 and LEU2 gene expression is controlled by alpha-Isopropylmalate and the product of a regulatory gene. Curr Genet 7(5):369-77
10) Natarajan K, et al.  (2001) Transcriptional profiling shows that Gcn4p is a master regulator of gene expression during amino acid starvation in yeast. Mol Cell Biol 21(13):4347-68
11) Wallace MA, et al.  (2004) Superoxide inhibits 4Fe-4S cluster enzymes involved in amino acid biosynthesis. Cross-compartment protection by CuZn-superoxide dismutase. J Biol Chem 279(31):32055-62