A high-throughput method has been developed to allow rapid analysis of maize seed storage proteins by matrix-assisted laser desorption time-of-flight mass spectrometry. The extraction solution containing an organic solvent, a reducing agent, and a volatile base has been optimized to enable extraction of all classes of zein proteins (alpha-, beta-, gamma-, and delta-). A near-saturating concentration of matrix, 2-(4-hydroxyphenylazo)benzoic acid, was necessary to obtain strong peaks for the most lipophilic zeins, the alpha-zeins. Zein proteins with small mass differences, difficult to separate by sodium dodecyl sulfate polyacrylamide gel electrophoresis, were resolved through this analysis. Mass signals corresponding to the 10-kDa delta-, 15-kDa beta-, 16-kDa gamma-, 27-kDa gamma-, and several 19 and 22-kDa alpha-zeins were detected. The zein identities were further confirmed by the association of the number of cysteine residues in each zein MS peak, as determined by iodoacetamide derivatization, with the number predicted from its coding sequence. The relative zein abundance in the zein MS peaks was also correlated with the relative zein EST abundance among endosperm EST libraries. This method was utilized to examine the zein composition of a number of corn inbred lines and opaque mutants.
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http://dx.doi.org/10.1021/jf034223v | DOI Listing |
J Am Soc Mass Spectrom
January 2025
Laboratory of Chemistry and Technology of Polymers and Colors, Department of Chemistry, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece.
Biobased poly(ethylene furanoate) (PEF)/poly(ε-caprolactone) (PCL) block copolymers have been synthesized using ring opening polymerization (ROP) of ε-caprolactone (ε-CL) in the presence of PEF in different mass ratios. An increase in intrinsic viscosity is observed for the block copolymers with higher ε-CL content due to the extension of their macromolecular chain. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MS) was employed to understand the composition and structure of the produced block copolymers.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Neurophysiology & Behaviour Lab, University of Castilla-La Mancha, Ciudad Real, Spain.
Background: A key neuropathological feature in the early stages of Alzheimer's disease (AD) involves hippocampal dysfunction arising from the accumulation of amyloid-β (Aβ). Previously, our laboratory identified a shift in the synaptic plasticity long term potentiation (LTP)/long term depression (LTD) induction threshold, leading to memory deficits in a non-transgenic murine model of early AD generated by intracerebroventricular (icv.) injections Aβ oligomers (oAβ), one of the most predominant pathogenetic factors in initial stages of the disease.
View Article and Find Full Text PDFBackground: Abnormal amyloid-β (Aβ) deposition in the brain has been defined as the earliest pathological change of Alzheimer disease (AD). Immunoprecipitation coupled with MALDI-TOF MS (IP-MS) has previously revealed that APP669-711/Aβ1-42 ratio, Aβ1-40/Aβ1-42 ratio, and a combination of these two biomarkers (a composite biomarker) in human plasma correlates highly with SUVR obtained from amyloid PET. In this work, we investigate the usefulness of plasma Aβ biomarkers at baseline in predicting the conversion to AD dementia.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
Background: Amyloid β (Aβ) deposition in the brain is a pathological hallmark of Alzheimer's disease (AD). While immunoprecipitation-mass spectrometry (IP-MS) stands out as an accurate method for quantifying blood-based Aβ peptides, its major limitations such as prolonged sample preparation, extensive analysis time, large specimen volume, and high costs, present opportunities for improvement. Consequently, we aimed to develop a novel plasma IP-MS Aβ assay that employs simplified and significantly shorter analytical procedures, along with much-reduced sample volumes.
View Article and Find Full Text PDFBackground: The rapidly growing pipeline of target-specific Alzheimer's Disease (AD) therapeutic candidates requires accompanying tests that can identify patients likely to have a beneficial response. The growing importance of multiple pathologies in determining AD progression and treatment response underscores this need. Our work focuses on establishing analytical capability to expand detectable forms of major protein drug targets for AD: Tau, amyloid beta (Ab) and a-Synuclein (aS) proteoforms as potential personalized molecular signatures.
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