# Proteomics Analysis of _Zygosaccharomyces mellis_ in Response to Sugar Stress
## 3 Results
### iTRAQ Data Analysis  
The mechanism of sugar tolerance in _Z. mellis_ was analyzed by proteomic techniques. The results showed that there were 522 DEPs in the 60% glucose YPD group compared with the 2% glucose YPD group, of which 303 (58.05%) were upregulated and 219 (41.95%) were downregulated (Table S3). Detailed information about the DEPs, including protein sequences and the values of SD, are listed in Table S4. According to the KOG functional categories, DEPs were classified into 23 groups. Among them, most DEPs were related to post-translational modification, protein turnover and chaperones (16.19%), amino acid transport and metabolism (15.19%), and energy production and conversion (14.85%). Additionally, formate dehydrogenase (FDH1), which catalyzes the decomposition of formic acid to produce CO\({}_{2}\) and the reduction of NAD+ to NADH, showed a great increase in response to high sugar stress [15]. The DEPs involved in the metabolic pathway of trehalose, glycerol and the TCA cycle, etc., are listed in Table 3. Among them, the proteins related to trehalose and glycerol degradation were all downregulated, and most of the proteins related to the glycolysis and pentose phosphate pathways were also downregulated. In contrast, most proteins related to TCA and respiration were upregulated.  
\begin{table}
\begin{tabular}{l c c} \hline \hline
**Protein\_ID** & **Description** & **60\% Glucose Group vs. 2\% Glucose Group** \\ \hline TCA cycle & & \\ GCE97816.1 & NAD-dependent isocitrate & 1.33 \\ GCF00601.1 & phosphoglycerate kinase & 0.74 \\ GCE97119.1 & cytochrome b subunit of succinate & 1.25 \\ dehydrogenase, Sdh3p & 1.25 \\ GCE99324.1 & NADP-dependent isocitrate & 0.44 \\ GCF01027.1 & malate dehydrogenase, cytoplasmic & 1.25 \\ GCE98908.1 & 2-oxoglutate dehydrogenase & 1.28 \\ GCE99351.1 & citrate (Si)-synthase & 1.29 \\ GCF00374.1 & succinate dehydrogenase complex, & 1.58 \\  & subunit B & \\ GCE97219.1 & succinate dehydrogenase assembly & 0.79 \\ GCF01476.1 & membrane anchor subunit of & 1.48 \\ Glycolysis & & \\ GCF00125.1 & glucokinase & 0.58 \\ GCF00259.1 & hexokinase A & 0.64 \\ GCE99269.1 & fructose-bisphosphate aldolase 1 & 0.69 \\ GCE98585.1 & glyceraldehyde-3-phosphate & 1.33 \\ GCE97503.1 & glyceraldehyde-3-phosphate & 1.21 \\ Pentose phosphate pathway & & \\ GCF00070.1 & enolase-phosphatase E1 & 0.55 \\ GCE97493.1 & ribulose-phosphate 3-epimerase & 0.67 \\  & sedoheptulose-7-phosphate: & \\ GCF01076.1 & D-glyceraldehyde-3-phosphate & 0.69 \\  & transaldolase & \\ GCF01082.1 & glucose-6-phosphate isomerase & 0.78 \\ GCE98569.1 & triorespphosphate isomerase & 0.8 \\  & glucose-6-phosphate & 1.25 \\ GCF01275.1 & 1-dehydrogenase & 1.55 \\ GCF00672.1 & ribose-5-phosphate isomerase ki1 & 1.55 \\ Respiratory chain & & \\ GCF00431.1 & ubiquitin-cytochrome c reductase & 1.4 \\  & core subunit 10 qcr10 & 0.48 \\ GCE98211.1 & NADH: ubiquitin coincidenceductase & 0.48 \\ GCF01526.1 & cytochrome c oxidase subunit 6 & 0.81 \\ GCE97076.1 & cytochrome c oxidase subunit 4 & 1.26 \\ GCF00071.1 & iso-1-cytochrome c & 1.29 \\ GCF01652.1 & cytochrome c oxidase subunit 2 & 1.3 \\  & GCE99676.1 & Cu-binding protein & 1.31 \\ Trehalose and glycerol degradation & & \\ GCE99412.1 & phosphoglucomutase-2 & 0.62 \\ GCF00370.1 & glycerol kinase & 0.79 \\  & glycerol-3- & \\ GCE99841.1 & phosphate/dihydroxyacetone & 0.83 \\  & phosphate acyltransferase & \\ GCE98648.1 & dihydroxyacetone kinase 1 & 0.72 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Partial DEPs of _Z. mellis_ in response to sugar stress.