Matrix-dependent a/x pair and overdegraded w/y/z ions generated by radical-directed dissociation of peptide radical cations [M] in matrix-assisted laser desorption/ionization in-source decay.

Fragmentation of peptide radical cations [M] has been examined using matrix-assisted laser desorption/ionization (MALDI) in-source decay (ISD) with hydrogen-abstracting nitro-substituted matrices. The ISD spectra of peptides containing an arginine (Arg) residue at carboxyl (C)-termini showed preferential [w] ions when 4-nitro-1-naphthol (4,1-NNL) matrix was used, whereas the use of 3,5-dinitrosalicylic acid (3,5-DNSA) resulted in preferential [x] ions. Minor or some [d] , [x] , [y] , and [z] ions were also observed.

Multiple Hydrogen Loss from [M + H] and [a] ions of Peptides in MALDI In-Source Decay Using a Dinitro-Substituted Matrix.

The formation and radical-directed dissociation of multiple hydrogen-abstracted peptide cations [M + H - mH]· has been reported using MALDI-ISD with dinitro-substituted matrices. The MALDI-ISD of synthetic peptides using 3,5-dinitrosalicylic acid (3,5-DNSA) and 3,4-dinitrobenzoic acid (3,4-DNBA) as matrices resulted in multiple hydrogen abstraction from the analyte [M + H] and fragment [] ions, i.e.

Variation in chemical composition of corn dried distillers grains with solubles in relation to in situ protein degradation profiles in the rumen.

Chemical composition and in situ degradation profiles were analyzed for 27 samples of dried distillers grains with solubles (DDGS) distributed in Japan, and a wide variation was found in neutral detergent fiber (NDF) content, which had positive relationships to detergent-insoluble crude proteins such as neutral detergent-insoluble crude protein (NDICP) and acid detergent-insoluble CP (ADICP). Samples with lower NDF (< 35% on dry matter (DM)) showed higher soluble fractions of protein, but the degradation rate of microbially degradable protein in the rumen was not different in comparison with the samples with higher NDF, and no difference was shown between samples with higher and lower NDF after 24 and 48 h of in situ incubation for DM and CP degradation, respectively. The NDICP content in the digestion residue decreased with time of incubation, especially for samples with higher NDF, while the ADICP content increased.

Sphingosine 1-phosphate acts as a signal molecule in ceramide signal transduction of TNF-alpha-induced activator protein-1 in osteoblastic cell line MC3T3-E1 cells.

We previously demonstrated that tumor necrosis factor (TNF)-alpha stimulated the production of activation protein (AP)-1, a transcriptional factor, in mouse osteoblastic MC3T3-E1 cells. Recent studies have shown the importance of ceramide and its metabolites as signal molecules for TNF-alpha-induced gene expression in several cell types. Therefore, our interest was to investigate whether sphingosine metabolites are involved in TNF-alpha-induced signaling in MC3T3-E1 cells.