Based on the in-house database MWDB (Metware Database), qualitative analysis was performed using the MS1 and MS2 spectra obtained from mass spectrometry detection. For the identification of certain substances, isotopic signals, redundant signals from K+, Na+, and NH4+ adduct ions, as well as redundant signals originating from fragment ions of other larger-molecular-weight compounds, were removed during analysis.
"],"repository":["MetaboLights"],"study_status":["Public"],"ptm_modification":[""],"instrument_platform":["Liquid Chromatography MS - negative - reverse-phase","Liquid Chromatography MS - positive - reverse-phase"],"chromatography_protocol":["The sample extracts were analyzed using an UPLC-ESI-MS/MS system (UPLC, ExionLC™ AD, https://sciex.com.cn/) and Tandem mass spectrometry system (https://sciex.com.cn/). The analytical conditions were as follows, UPLC: column, Agilent SB-C18 (1.8 μm, 2.1 mm all_fetch_status all_status eb_eye_copy_status eb_eye_entry_counts eb_eye_fetch_status eb_eye_metabolights_complete.xml eb_eye_metabolights_compounds.copy eb_eye_metabolights_compounds.xml eb_eye_metabolights_studies.copy e_fetch_status europe_PMC_metabolights_studies.copy europe_PMC_metabolights_studies.xml head.xml studies.copy study.xml tail.xml thomsonreuters_metabolights_studies.copy thomsonreuters_metabolights_studies.xml 100 mm); The mobile phase was consisted of solvent A, pure water with 0.1% formic acid, and solvent B, acetonitrile with 0.1% formic acid. Sample measurements were performed with a gradient program that employed the starting conditions of 95% A, 5% B. Within 9 min, a linear gradient to 5% A, 95% B was programmed, and a composition of 5% A, 95% B was kept for 1 min. Subsequently, a composition of 95% A, 5.0% B was adjusted within 1.1 min and kept for 2.9 min. The flow velocity was set as 0.35 mL per minute; The column oven was set to 40°C; The injection volume was 2 μL. The effluent was alternatively connected to an ESI-triple quadrupole-linear ion trap (QTRAP)-MS.
"],"publication":["A Plastoglobuli-Localized Enzyme Links Phenylalanine Biosynthesis to Translational Homeostasis in Maize."],"submitter_name":["Xing Huang"],"submitter_affiliation":["CAS Center for Excellence in Molecular Plant Sciences"],"organism_part":["endosperm"],"technology_type":["mass spectrometry assay"],"disease":[""],"extraction_protocol":["Using vacuum freeze-drying technology, place the biological samples in a lyophilizer (Scientz-100F), then grinding (30 Hz, 1.5 min) the samples to powder form by using a grinder (MM 400, Retsch). Next, weigh 50 mg of sample powder using an electronic balance (MS105DΜ) and add 1200 μL of -20 °C pre-cooled 70% methanolic aqueous internal standard extract (less than 50 mg added at the rate of 1200 μL extractant per 50 mg sample). Vortex once every 30 min for 30 sec, for a total of 6 times. After centrifugation (rotation speed 12000 rpm, 3 min), the supernatant was aspirated, and the sample was filtered through a microporous membrane (0.22 μm pore size) and stored in the injection vial for UPLC-MS/MS analysis.
"],"organism":["Zea mays cv. B73"],"full_dataset_link":["https://www.ebi.ac.uk/metabolights/MTBLS14848"],"author":["Xing Huang. CAS Center for Excellence in Molecular Plant Sciences. huangxing@cemps.ac.cn.","yongrui Wu. CAS Center for Excellence in Molecular Plant Sciences. yrwu@cemps.ac.cn."],"data_transformation_protocol":["The raw data files generated after mass spectrometry analysis were opened and reviewed using Analyst 1.6.3 software, and subsequently used for qualitative and quantitative analysis. Quantification was carried out using the multiple reaction monitoring (MRM) mode of a triple quadrupole mass spectrometer (as shown in the figure below). In MRM mode, the first quadrupole selects the precursor ion (parent ion) of the target compound, excluding ions corresponding to other molecular weights to preliminarily eliminate interferences. The precursor ions are then induced to dissociate in the collision cell, generating numerous fragment ions. The third quadrupole filters and selects one specific characteristic fragment ion, thereby excluding non-target ion interferences, which results in more accurate quantification and better reproducibility. After obtaining the metabolomic mass spectrometry data from different samples, peak area integration was performed for all metabolite peaks, and the chromatographic peaks of the same metabolite across different samples were subjected to integration correction.
The 18-DAP B104 and adt2.2 endosperm were collected and immediately frozen in liquid nitrogen. The endosperm was then ground into fine powder.
"],"omics_type":["Metabolomics"],"study_design":["Metabolomics","SCIEX ExionLC AD","targeted analysis","Zea mays cv. B73","ADT2.2","liquid chromatography-tandem mass spectrometry","Maize","experimental blank","AB SCIEX QTRAP 6500","endosperm"],"curator_keywords":["Metabolomics","SCIEX ExionLC AD","targeted analysis","ADT2.2","Zea mays cv. B73","liquid chromatography-tandem mass spectrometry","Maize","experimental blank","AB SCIEX QTRAP 6500","endosperm"],"mass_spectrometry_protocol":["The ESI source operation parameters were as follows: source temperature 500°C; ion spray voltage (IS) 5500 V (positive ion mode)/-4500 V (negative ion mode); ion source gas I (GSI), gas II(GSII), curtain gas (CUR) were set at 50, 60, and 25 psi, respectively; the collision-activated dissociation(CAD) was high. QQQ scans were acquired as MRM experiments with collision gas (nitrogen) set to medium. DP(declustering potential) and CE(collision energy) for individual MRM transitions was done with further DP and CE optimization. A specific set of MRM transitions were monitored for each period according to the metabolites eluted within this period.
"],"additional_accession":[]},"is_claimable":false,"name":"A Plastoglobuli-Localized Enzyme Links Phenylalanine Biosynthesis to Translational Homeostasis in Maize","description":"Aromatic amino acids are essential precursors for numerous plant metabolites, with phenylalanine (Phe) forming the basis of the phenylpropanoid pathway. Here, we reveal a critical mechanism for Phe biosynthesis in maize, demonstrating that all seven arogenate dehydratases (ADTs) are specifically localized to plastoglobuli (PGs) in chloroplasts, and ADT2.2 shows high catalytic activity towards arogenate and prephenate. This discovery establishes PGs as a site for Phe synthesis. Genetic analysis confirms that only ADT2.2 is indispensable for plant and seed development, with its loss causing a severe Phe deficiency in seeds. This metabolic blockage directly reduced the tRNAPhe-GAA charging, thereby repressing protein translation. Crucially, we uncover that Phe starvation disproportionately affects the decoding efficiency of wobble-paired codons, increasing ribosome pausing. Our work provides biochemical and genetic evidence that PGs-localized ADT2.2 catalyzes Phe synthesis and reveals a link between amino acid availability and codon-specific translation dynamics.
","dates":{"publication":"2026-06-25","submission":"2026-06-24"},"accession":"MTBLS14848","cross_references":{}}