| Study / system | Quantitative parameter | Value(s) | Interpretation / note | Citation |
|---|---|---|---|---|
| Zhang et al. 2024, hybrid poplar cambium under nitrogen treatments | Nitrogen levels | L = 0.15 mM NH4NO3; LM = 0.3 mM; M = 1 mM; HM = 3 mM; H = 5 mM | Experimental gradient used to probe nitrogen effects on cambium development and phenylpropanoid flux | (pqac-00000013, pqac-00000015, pqac-00000017) |
| Zhang et al. 2024, hybrid poplar cambium | DEG counts vs. 1 mM control (M) | M vs L: 2365; M vs LM: 824; M vs HM: 649; M vs H: 398 | Largest transcriptional shift occurred under the lowest N treatment | (pqac-00000013, pqac-00000015) |
| Zhang et al. 2024, hybrid poplar cambium | Up/down DEG breakdown | M vs L: 1183 up, 1182 down; M vs LM: 615 up, 209 down; M vs HM: 236 up, 413 down; M vs H: 89 up, 309 down | Low N favored broader induction of genes, including phenylpropanoid-pathway genes | (pqac-00000013) |
| Zhang et al. 2024, hybrid poplar cambium | DRM counts | M vs L: 359 (195 up, 164 down); M vs LM: 190 (120 up, 70 down); M vs HM: 81 (40 up, 41 down); M vs H: 138 (67 up, 71 down) | Metabolome response was also strongest under low N | (pqac-00000016) |
| Zhang et al. 2024, hybrid poplar cambium | Total annotated metabolites | 1,838 | Broad metabolome coverage for pathway-level inference | (pqac-00000016) |
| Zhang et al. 2024, hybrid poplar cambium | Phenylpropanoid-related metabolite direction under low N (L) | Caffeic acid decreased; coniferin increased | Supports rerouting toward lignin-associated phenylpropanoid output under low N | (pqac-00000014, pqac-00000018) |
| Zhang et al. 2024, hybrid poplar cambium | Phenylpropanoid gene-metabolite correlations | 35 DEGs linked with caffeic acid and coniferin under L; network threshold PCC >= 0.99 and p < 0.01 | PAL, C4H, 4CL, CCR, HCT, peroxidases, CAD, and F5H were negatively correlated with caffeic acid and positively correlated with coniferin | (pqac-00000014, pqac-00000018) |
| Zhang et al. 2024, hybrid poplar cambium | PAL-pathway gene expression trend | PAL, C4H, 4CL, C3H, COMT, F5H, and CCR significantly increased under L and LM vs M | Indicates low nitrogen promotes upstream phenylpropanoid entry and downstream lignification machinery | (pqac-00000016) |
| Zhang et al. 2024, hybrid poplar cambium | Structural and biochemical phenotype under low N | Cellulose decreased; lignin and hemicellulose increased; fiber cell wall thickness and lignin content significantly increased | Consistent with activation of lignin-biased phenylpropanoid flux | (pqac-00000013, pqac-00000017, pqac-00000018) |
| Padrosa et al. 2023, soluble AvPAL and PbPAL | Specific activity | AvPAL: 0.10 +/- 0.02 U/mg; PbPAL: 0.05 +/- 0.01 U/mg | Free-enzyme benchmark before immobilization and flow processing | (pqac-00000022) |
| Padrosa et al. 2023, free-enzyme batch biotransformations | Typical conditions | 10 mM cinnamic acid derivative, 2 M ammonium carbamate, pH 10, 37 C, 1 mL; 2 mg/mL free enzyme | Standardized synthetic PAL assay conditions | (pqac-00000022) |
| Padrosa et al. 2023, free-enzyme conversions | Representative conversions | Up to 85% conversion; PbPAL >60% after 24 h; 2 M ammonium carbamate gave >70% after 24 h | Shows practical equilibrium-limited amination performance | (pqac-00000022, pqac-00000026) |
| Padrosa et al. 2023, substrate scope examples | Representative substrate conversions | m-methoxy cinnamic acid: AvPAL 37% in 24 h and PbPAL 78% in 2 h; another methoxy substrate: AvPAL 70% in 2 h and PbPAL 87% in 2 h; p-NO2 substrate: 85% for both at 24 h; o,p-dichloro substrate: <5% AvPAL and 6% PbPAL at 48 h | Strong substrate dependence of PAL synthetic utility | (pqac-00000021) |
| Padrosa et al. 2023, immobilization | Immobilization yield and recovered activity | >90% immobilization yield; about 50% recovered activity; up to 60% recovered activity in some preparations | Covalent immobilization preserved substantial catalytic function | (pqac-00000022, pqac-00000024, pqac-00000026) |
| Padrosa et al. 2023, immobilized supports | Example support metrics | 10 mg protein/g support; EP400/SS 91% +/- 1% yield and 0.51 U/g; EP403/S 89% +/- 2% yield and 0.6 U/g | Quantifies immobilized catalyst preparation quality | (pqac-00000024) |
| Padrosa et al. 2023, continuous flow | Contact and retention time | About 20 min | Key process-intensification advantage versus batch | (pqac-00000023, pqac-00000024, pqac-00000026) |
| Padrosa et al. 2023, continuous flow | Product conversions | 88% +/- 4% for 3-methoxy-phenylalanine; 89% +/- 5% for 4-nitro-phenylalanine | High conversion maintained under flow for selected products | (pqac-00000026) |
| Padrosa et al. 2023, operational stability | Stability duration | Maintained up to 24 h; stable for at least 6 column volumes (2 h reaction, 3 h total); three 40 mL reuse runs up to 8 h each with no apparent loss | Demonstrates reusability and process robustness | (pqac-00000023, pqac-00000024, pqac-00000026) |
| Padrosa et al. 2023, process metrics | STY, catalyst productivity, and E-factor | STY: batch free enzyme 761.4, immobilized 74.8, continuous flow 2401.2; catalyst productivity: 0.8, 3.6, 8.0; E-factors about 763, 646, 725 | Flow increased space-time yield about 3-fold over free batch but waste remained high due to dilute substrate and ammonia use | (pqac-00000023, pqac-00000024) |
| Sun et al. 2024, engineered PcPAL whole-cell biocatalysis | Key variants | PcPAL-L256V-I460V double mutant; PcPAL-F137V-L256V-I460V triple mutant | Variants enabled beta-methyl cinnamic acid acceptance | (pqac-00000025) |
| Sun et al. 2024, engineered PcPAL products | Number of products | 10 beta-branched phenylalanine analogs | Demonstrates broadened synthetic scope | (pqac-00000025) |
| Sun et al. 2024, engineered PcPAL performance | Isolated yield | 41-71% | Practical preparative yields for difficult beta-branched products | (pqac-00000025) |
| Sun et al. 2024, engineered PcPAL selectivity | Diastereoselectivity and enantioselectivity | dr > 20:1; ee > 99.5% | Very high stereoselectivity for asymmetric synthesis | (pqac-00000025) |
| Kao et al. 2002, quaking aspen PtPAL1 | cDNA and ORF length | cDNA 2,413 bp; ORF 2,142 bp | Molecular definition of PtPAL1 used in tissue-specific expression studies | (pqac-00000002) |
| Kao et al. 2002, quaking aspen PtPAL1 | Protein length | 714 aa | PtPAL1 associated with CT-accumulating, non-lignifying cells | (pqac-00000002) |
| Kao et al. 2002, quaking aspen PtPAL2 | cDNA and ORF length | cDNA 2,515 bp; ORF 2,133 bp | Molecular definition of PtPAL2 used in tissue-specific expression studies | (pqac-00000002) |
| Kao et al. 2002, quaking aspen PtPAL2 | Protein length | 711 aa | PtPAL2 associated with lignifying structural tissues and root tips | (pqac-00000002) |


*Table: This table compiles numeric results relevant to PAL and phenylpropanoid flux from Populus and PAL biocatalysis studies. It supports quick comparison of poplar pathway regulation, engineered PAL process performance, and core molecular properties of poplar PAL isoforms.*