Enzymatic degradation structure

To date, the structural features of pectic polysaccharides and plant cell walls have been studied extensively using chemical analysis and enzymatic degradation. In addition, research on isolation and physicochemical characterisation of pectin from citrus peels, apple peels, sunflower head residues and sugar beet pulp has been reported (2). However, the pectic polysaccharides extracted from wheat straw have only previously been reported by Przeszlakowska (3). The author extracted 0.44% pectic substances from Author to whom correspondence should be addressed. 

Because of the easily oxidizable structure of the polyphenols previously described, many studies have been published about the enzymatic degradation of these antioxidant compounds. This chapter exhaustively reviews the main publications concerning the degradation of this type of antioxidant compound by several enzymes. 

Ishikawa, H., W. J. Schubert, and F. F. Nord The Enzymatic Degradation of Softwood Lignin by White Rot Fungi. The Degradation by Polyporus versicolor and Forties fomentarius of Aromatic Compounds Structurally Related to Softwood Lignin. Arch. Biochem. Biophys. 100, 131-149 (1963). 

The weakly immunogenic protamine sulfate USP (1) condenses DNA to form a toroid structure of super-coiled DNA about 50 nm in diameter (2). The DNA in this form or in the preformed LPDI complex cannot be displaced from the protamine by polycations such as spermidine and histones or by other nucleic acids like genomic DNA (2). DNA in this toroid structure is transcriptionally inactive and this conformation allows for protection of DNA from enzymatic degradation by nucleases and other environmental assaults such as mechanical stress (1,2). After the liposome surrounds the toroid, the resulting homogenous LPDI nanoparticles are slightly less than... 

Those siderophores with low molecular weight, nonpeptidal structures are anticipated to be stable to proteolytic enzymatic degradation, and less likely to evoke an immune response. The antibiotic can be selected from commercial sources or from a large arsenal of potential antibiotics with low solubility that were overlooked, or never underwent extensive clinical investigations. 

The structures of the compounds were elucidated by a combination of NMR techniques (lH-, 13C-, and 13C-DEPT NMR) and chemical transformation, enzymatic degradation, and as well as mass spectrometry, which gives information on the saccharide sequence. A more recent approach consists of an extensive use of high-resolution 2D NMR techniques, such as homonuclear and heteronuclear correlated spectroscopy (DQF-COSY, HOHAHA, HSQC, HMBC) and NOE spectroscopy (NOESY, ROESY), which now play the most important role in the structural elucidation of intact glycosides. These techniques are very sensitive and non destructive and allow easy recovery of the intact compounds for subsequent biological testing. 

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