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541.
A method based on Rimini test for aliphatic amines was studied and developed for quantitative estimation of aliphatic primary
amines. The method involves action of the amine with acetone to form schiff base which complexes with sodium nitroprusside
to give violet colour. The absorption maximum in the visible range of the spectrum, for the reaction mixture was found to
be 550 nm. The pH (8–11) and reaction time scan for the assay were optimized. A linear relation of concentration (0.2–3 mg/mL)
of amine against absorbance at 550 nm was established. Interference due to other reaction components was negligible (±0.02 mg/mL)
as compared to the sample in buffer. 1, 3-dimethyl butylamine was used as the model amine and the method was applied to other
amines; it was observed that when electron-withdrawing substituents are present in the molecule the reaction is retarded,
as the incubation time was longer. This method is useful for estimation of aliphatic primary amine in biological samples. 相似文献
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Protein AMPylation refers to the covalent attachment of an AMP moiety to the amino acid side chains of target proteins using ATP as nucleotide donor. This process is catalysed by dedicated AMP transferases, called AMPylases. Since this initial discovery, several research groups have identified AMPylation as a critical post-translational modification relevant to normal and pathological cell signalling in both bacteria and metazoans. Bacterial AMPylases are abundant enzymes that either regulate the function of endogenous bacterial proteins or are translocated into host cells to hijack host cell signalling processes. By contrast, only two classes of metazoan AMPylases have been identified so far: enzymes containing a conserved filamentation induced by cAMP (Fic) domain (Fic AMPylases), which primarily modify the ER-resident chaperone BiP, and SelO, a mitochondrial AMPylase involved in redox signalling. In this review, we compare and contrast bacterial and metazoan Fic and non-Fic AMPylases, and summarize recent technological and conceptual developments in the emerging field of AMPylation. 相似文献
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Background
For a proper understanding of protein structure and folding it is important to know if a polypeptide segment adopts a conformation inherent in the sequence or it depends on the context of its flanking secondary structures. Turns of various lengths have been studied and characterized starting from three-residue γ-turn to six-residue π-turn. The Schellman motif occurring at the C-terminal end of α-helices is a classical example of hydrogen bonded π-turn involving residues at (i) and (i+5) positions. Hydrogen bonded and non-hydrogen bonded β- and α-turns have been identified previously; likewise, a systematic characterization of π-turns would provide valuable insight into turn structures. 相似文献548.
Amit Kumar Rai H.C. Swapna N. Bhaskar P.M. Halami N.M. Sachindra 《Enzyme and microbial technology》2010,46(1):9-13
Fish viscera are an important source for biomolecules such as protein and lipids. Studies were carried out to assess fermentation ensilaging as a method for recovery of oil from fresh water fish viscera. The total lipid content in the viscera ranged from 19% to 21% and upto 85% of this could be recovered by fermentation. Fermentation using added lactic cultures (Enterococcus faecium HAB01 and Pediococcus acidilactici K7) did not show any advantage over natural fermentation with respect to recovery of oil and no differences were observed in fatty acid composition of oil recovered by fermentation using different cultures. Activity of acidic, neutral and alkaline proteases decreased during fermentation. Eventhough degree of protein hydrolysis increased during fermentation with highest (62.3%) being in fermentation using Pediococcus acidilactici K7 no differences were found in oil recovery. With decrease in protease activity the rate of change in degree of hydrolysis also decreased. 相似文献
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