Studies on the biotransformation of isoxazole rings have shown that molecules containing a C3-substituted isoxazole or a 1,2-benzisoxazole can undergo a two-electron reductive ring cleavage to form an imine. In the absence of a C3 substituent, the isoxazole ring opens via deprotonation of the C3 proton followed by N-O bond cleavage to yield an α-cyanoenol analog. We report the identification of...

Camptothecin (CPT) analogues are powerful anticancer agents but are chemically unstable due to their alpha-hydroxylactone six-membered E-ring structure, which is essential for trapping topoisomerase I (Top1)-DNA cleavage complexes. To stabilize the E-ring, CPT keto analogues with a five-membered E-ring lacking the oxygen of the lactone ring (S38809 and S39625) have been synthesized. S39625 has ...

A protocol is presented for the quantitative conversion of cysteine and cystine residues in proteins to residues of Scyanocysteine, using the reagent 2-nitro-S-thiocyanobenzoic acid (DEGANI, Y., AND PATCHORNIK, A. (1971) J. Org. Chem. 36, 2727). Cleavage of the amino peptide bond of the Scyanocysteine residue is obtained upon exposure to 6 M guanidinium chloride-O.1 M sodium borate, pH 9.0, at ...

When fed the right food, hermit crab depicted in cover image grows bigger and finally needs a larger shell. This work reports reactivity of 1-phospha-2-azanorbornene, product hetero Diels-Alder reaction between 2H-phosphole an activated imine. Thus, reductive cleavage phosphorus−nitrogen bond with LiAlH4 leads to unprecedented ring expansion formation 1-phosphabicyclo[3.2.1]octa-2,5-diene. The ...

Pseudomonas sp. strain HBP1 Prp grew on 2-isopropylphenol as the sole carbon and energy source with a maximal specific growth rate of 0.14 h-1 and transient accumulation of isobutyric acid. Oxygen uptake experiments with resting cells and enzyme assays with crude-cell extracts showed that 2-isopropylphenol was catabolized via a broad-spectrum meta cleavage pathway. These findings were confirmed...

Cytokinesis is a highly ordered cellular process driven by interactions between central spindle microtubules and the actomyosin contractile ring linked to the dynamic remodelling of the plasma membrane. The mechanisms responsible for reorganizing the plasma membrane at the cell equator and its coupling to the contractile ring in cytokinesis are poorly understood. We report here that Syndapin, a...

Derivatives were prepared from N-linked glycans by reductive amination from 2-aminobenzamide, 2-aminopyridine, 3-aminoquinoline, 2-aminoacridone, 4-amino-N-(2-diethylaminoethyl)benzamide, and the methyl, ethyl, and butyl esters of 4-aminobenzoic acid. Their electrospray and collision-induced dissociation (CID) fragmentation spectra were examined with a Q-TOF mass spectrometer. The strongest sig...

Phycoerythrobilin and phycocyanobilin are covalently attached to the apoproteins of phycoerythrins and phycocyanins. One linkage consists of an ester bond between the hydroxy group of a serine residue and the propionate side chain on one of the inner pyrrole rings (probably ring C). The other linkage is a labile thioether bond between a cysteine residue and the two-carbon side chain on pyrrole ...

While the properties of biochar are closely related to its functional groups, it is unclear under what conditions biochar develops its properties. In this study, two-dimensional (2D) (13)C nuclear magnetic resonance (NMR) correlation spectroscopy was for the first time applied to investigate the development of functional groups and establish their relationship with biochar properties. The resul...

Rearrangement and fragmentation patterns, which have been observed during uv. irradiation of the following pyridinium ylides, will be discussed: pyridinium methylides, N.-iminopyridinium ylides and pyridine-N--oxides. As a rule these mesoionic compounds undergo two competing reactions: i) photolytic cleavage via a triplet state, leading to the corresponding pyridines and to carbenes, nitrenes a...