Two series of Schiff base metal complexes were investigated, where each series was supported by an ancillary ligand incorporating a ferrocene backbone and different N=X functionalities. One ligand is based on an imine, while the other is based on an iminophosphorane group. Cerium(IV), cerium(III), and yttrium(III) alkoxide complexes supported by the two ligands were synthesized. All metal complexes were characterized by cyclic voltammetry. Additionally, NMR, Mössbauer, X-ray absorption near-edge structure (XANES), and absorption spectroscopies were used. The experimental data indicate that iron remains in the +2 oxidation state and that cerium(IV) does not engage in a redox behavior with the ancillary ligand.

We disclose a protocol for the palladium-catalyzed ortho-selective C-H deuteration of arenes. Phenylacetic acids and benzoic acids are suitable substrates for this reaction. This reaction offers a catalytic route to ortho-deuterated phenylacetic acids and benzoic acids and demonstrates the sharp difference in reactivity of palladacycle intermediates held together by weak and strong coordination.

A highly efficient ligand-accelerated Pd(II)-catalyzed C(sp2)–H/arylboron cross-coupling reaction of phenylacetic acid substrates is reported. Using Ac-Ile-OH as the ligand and Ag2CO3 as the oxidant, a fast, high yielding, operationally simple, and functional group–tolerant protocol has been developed for the cross-coupling of phenylacetic acid substrates with aryltrifluoroborates. This ligand scaffold has also been shown to improve substantially catalysis using 1 atm O2 as the sole reoxidant, which sheds light on the path forward in developing optimized ligands for aerobic C–H/arylboron cross-coupling.

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A protocol for the Pd(II)-catalyzed ortho-C–H alkylation of phenylacetic and benzoic acids using alkylboron reagents is disclosed. Mono-protected amino acid ligands (MPAA) were found to significantly promote reactivity. Both potassium alkyltrifluoroborates and alkylboronic acids were compatible coupling partners. The possibility of a radical alkyl transfer to Pd(II) was also investigated.

Quantitative metaproteomics and activity-based protein profiling of patient fecal microbiome identifies host and microbial serine-type endopeptidase activity associated with ulcerative colitis.

We designed a metaproteomic analysis method (ComPIL) to accommodate the ever-increasing number of sequences against which experimental shotgun proteomics spectra could be accurately and rapidly queried. Our objective was to create these large databases for the analysis of complex metasamples with unknown composition, including those derived from human, animal, and environmental microbiomes. The amount of high-throughput sequencing data has substantially increased since our original database was assembled in 2014. Here, we present a rebuild of the ComPIL libraries comprised of updated publicly disseminated sequence data as well as a modified version of the search engine ProLuCID-ComPIL optimized for querying experimental spectra. ComPIL 2.0 consists of 113 million protein records and roughly 4.8 billion unique tryptic peptide sequences and is 2.3 times the size of our original version. We searched a data set collected on a healthy human gut microbiome proteomic sample and compared the results to demonstrate that ComPIL 2.0 showed a substantial increase in the number of unique identified peptides and proteins compared to the first ComPIL version. The high confidence of protein identification and accuracy demonstrated by the use of ComPIL 2.0 may encourage the method’s application for large-scale proteomic annotation of complex protein systems.

Dysregulated protease activity is often implicated in the initiation of inflammation and immune cell recruitment in gastrointestinal inflammatory diseases. Using N-terminomics/TAILS (terminal amine isotopic labeling of substrates), we compared proteases, along with their substrates and inhibitors, between colonic mucosal biopsies of healthy patients and those with ulcerative colitis (UC). Among the 1642 N-termini enriched using TAILS, increased endogenous processing of proteins was identified in UC compared to healthy patients. Changes in the reactome pathways for proteins associated with metabolism, adherens junction proteins (E-cadherin, liver-intestinal cadherin, catenin alpha-1, and catenin delta-1), and neutrophil degranulation were identified between the two groups. Increased neutrophil infiltration and distinct proteases observed in ulcerative colitis may result in extensive break down, altered processing, or increased remodeling of adherens junctions and other cellular functions. Analysis of the preferred proteolytic cleavage sites indicated that the majority of proteolytic activity and processing comes from host proteases, but that key microbial proteases may also play a role in maintaining homeostasis. Thus, the identification of distinct proteases and processing of their substrates improves the understanding of dysregulated proteolysis in normal intestinal physiology and ulcerative colitis.P roteases are implicated in key functions during gastrointestinal (GI) homeostasis, and dysregulated proteolysis is one of the contributing factors of gastrointestinal inflammatory diseases. 1−3 Upon recruitment to the site of inflammation, activated immune cells produce various intraand extra-cellular proteases including neutrophil elastase (NE), matriptase, cathepsins, caspases, and matrix metalloproteinases, which all play roles in modulating the host response. 4−7 The shift in the balance between regulated and dysregulated proteolysis in GI inflammation is not fully understood, and the full repertoire of proteases, their substrates, and their inhibitors has not been examined in detail. Transcript analyses have been performed on samples from patients with inflammatory bowel diseases, 8 but mRNA levels often do not correlate with protein levels. 9 Furthermore, transcriptomics does not assess whether a substrate is cleaved or not by a