Table 1.
Overview of the major genes, related flavor compounds and encoded enzymes, responsible for flavor compound synthesis in yeast.
| Enzymes involved in higher alcohol and ester biosynthesis in S. cerevisiae | |||
|---|---|---|---|
| Gene name | Related flavor compounds | Major function/enzymatic activity | Cellular compartment |
| ADH1 | Higher alcohols | Alcohol dehydrogenase | Cytoplasm |
| ADH2 | Higher alcohols | Alcohol dehydrogenase | Cytoplasm |
| ADH3 | Higher alcohols | Alcohol dehydrogenase | Mitochondrion |
| ADH4 | Higher alcohols | Alcohol dehydrogenase | Mitochondrion |
| ADH5 | Higher alcohols | Alcohol dehydrogenase | Cytoplasm/nucleus |
| ARO10 | 2-Phenylethanol | Phenylpyruvate decarboxylase | Cytoplasm |
| ARO3 | 2-Phenylethanol | 3-Deoxy-d-arabino-heptulosonate-7-phosphate (DAHP) synthase | Cytoplasm |
| ARO4 | 2-Phenylethanol | 3-Deoxy-d-arabino-heptulosonate-7-phosphate (DAHP) synthase | Cytoplasm |
| ARO7 | 2-Phenylethanol | Chorismate mutase | Cytoplasm |
| ATF1 | Acetatete esters | Alcohol acetyl-coA transferase | Lipid droplets |
| ATF2 | Acetatete esters | Alcohol acetyl-coA transferase | Endoplasmic reticulum |
| BAT1 | Higher alcohols and other aroma compounds | Branched-chain amino acid transferase | Mitochondrion |
| BAT2 | Higher alcohols and other aroma compounds | Branched-chain amino acid transferase | Cytoplasm |
| BTS1 | Terpenoids | Farnesyltranstransferase/Geranylgeranyl diphosphate (GGPP) synthase; terpenoid backbone biosynthesis (C10-C20 isoprenoid biosynthesis) | Endoplasmic reticulum |
| COQ1 | Monoterpenoids | Trans-hexaprenyltranstransferase/hexaprenyl pyrophosphate synthase; isoprene biosynthesis, the pathway of ubiquinone biosynthesis, which is part of Cofactor biosynthesis | Mitochondrion |
| EAT1 | Ethyl acetate | Ethanol acetyl-coA transferase | Mitochondrion |
| EEB1 | Ethyl hexanoate | Ethanol acyl-coA transferase | Unknown |
| EHT1 | Ethyl hexanoate | Ethanol acyl-coA transferase | Lipid droplets/mitochondrion |
| ERG12 | Terpenoids | Mevalonate kinase; phosphorylation of mevalonate to mevalonate 5-phosphate | Cytoplasm |
| ERG20 | Terpenoids | Farnesyl diphosphate (FPP) synthase/dimethylallyltranstransferase; terpenoid backbone biosynthesis (C10-C20 isoprenoid biosynthesis) | Cytoplasm |
| ERG8 | Terpenoids | Phosphomevalonate kinase; isopentenyl diphosphate biosynthesis via mevalonate pathway | Cytoplasm |
| EXG1 | Terpenoids | Exo-(1,3)-β-glucanase(β-glucosidase activity) | Periplasm/extracellular secretion |
| HMG1 | Terpenoids | Hydroxymethylglutaryl-coA reductase reductase | Endoplasmic reticulum/nuclear envelope |
| IAH1 | Acetate esters(isoamyl acetate) | Isoamyl acetate-hydrolyzing esterase | Cytoplasm |
| IDI1 | Monoterpenoids | Isopentenyl-diphosphate (IPP) isomerase; terpenoid backbone biosynthesis (rearrangement of IPP to DMAPP) | Cytoplasm/nucleus |
| IRC7 | Polyfunctional thiols (4-Sulfanyl-4-methylpentan-2-one) | Carbon-sulfur b-lyase | Cytoplasm |
| LEU4 | Isoamyl alcohol | a-Isopropylmalate synthase | Mitochondrion/cytoplasm |
| MVD1 | Terpenoids | Diphosphomevalonate decarboxylase; isopentenyl diphosphate biosynthesis | Cytoplasm |
| OYE2 | Geraniol → citronellol | NADPH dehydrogenase 2 (old yellow enzyme 2); geraniol reduction into citronellol | Cytoplasm/mitochondrion/nucleus |
| PLB2 | Ethyl octanoate | Lysophospholipase(ethanol acyl-coA transferase activity) | Membrane/periplasm/extracellular secretion |
| SFA1 | Higher alcohols | Alcohol dehydrogenase | Cytoplasm |
| SRT1 | Monoterpenoids | Prenyl diphosphate synthase; terpenoid backbone biosynthesis | Lipid droplet/endoplasmic reticulum |
| STR3 | Polyfunctional thiols (3-Sulfanylhexanol) | Cystathionine b-lyase (carbon-sulfur b-lyase activity) | Peroxisome |
| Microbial enzymes in terpenoid biosynthesis or biotransformation | |||
| GEOA | Geraniol → geranial | NAD+-dependent geraniol dehydrogenase; geraniol dehydration | Carpoglyphus lactis and Castellaniella defragrans |
| GEOB | Geranial → geranic acid | NAD+-dependent geranial dehydrogenase; geranial dehydration | Carpoglyphus lactis and Castellaniella defragrans |
| LDI | Myrcene → linaloollinalool → myrcenegeraniol → linaloollinalool → geraniol | Linalool dehydratase/geraniol isomerase; myrcene hydration, linalool dehydration, linalool and geraniol isomerization | Castellaniella defragrans |
| Enzymes involved in terpenoid biosynthesis in hop (Humulus lupulus) | |||
| GPPS | Terpenoids | GPP synthase | Plastidic |
| MTS1 | Monoterpenoids | Monoterpene synthase | Plastidic |
| MTS2 | Monoterpenoids (myrcene) | Monoterpene synthase | Plastidic |
| STS1 | Sesquiterpenoids (humulene and caryophyllene) | Sesquiterpene synthase | Cytoplasm |
| STS2 | Sesquiterpenoids(b-elemene) | Sesquiterpene synthase | Cytoplasm |