ERG1 (YGR175C) notes

UniProt P32476; squalene epoxidase, EC 1.14.14.17; FAD (by similarity) [UniProt:P32476].

Evidence journal

• Cloned from allylamine-resistant mutant; extract activity terbinafine-resistant PMID:1743514.
• Microsomal enzyme needs NADPH, not added FAD PMID:8358382.
• Dual ER/LD localisation; activity only in ER PMID:9450962.
• erg1 mutants lack the activity PMID:200835.
• Constitutive LD protein PMID:24868093.

Decisions

• All squalene monooxygenase rows ACCEPT; RCA cytosol -> MODIFY ER membrane (converter default); ARBA ergosterol metabolic -> MODIFY biosynthetic; membrane IEA -> ER membrane; triterpenoid BP and FAD binding KEEP_AS_NON_CORE.

2026-11-06 re-review

• just deep-research-falcon yeast ERG1 failed because the Falcon provider is not available in this environment (agentapi missing; only claude_code listed). No provider-named deep-research file was created.
• A 2024 substrate-tunnel engineering paper on S. cerevisiae Erg1 further supports the existing squalene epoxidase/ergosterol-biosynthesis call but does not add a new GO function: "the catalytic activity of the squalene epoxidase from Saccharomyces cerevisiae was significantly improved by reshaping its substrate tunnel" PMID:39454051.