Proteinaceous polysaccharide

Over the centuries the natural organic materials that have best met these requirements are proteinaceous materials (egg, animal glue and casein or milk), polysaccharide gums... 

The following sections discuss in detail the Py-GC/MS of proteinaceous materials, oils and fats, and then briefly plant and animal resins, polysaccharide materials, and beeswax. Particular attention is given to the application of this analytical technique to characterise samples from works of art. At the end of the chapter four case studies are presented. 

The usual problems encountered in the isolation of natural polysaccharides, such as removal of proteinaceous matter or lignin, are absent in the isolation of synthetic polysaccharides. Consequently, the problem of degradation during isolation184-984 is not serious. 

Stainsby, G. (1980). Proteinaceous gelling systems and their complexes with polysaccharides. Food Chem. 6 3-14. 

Alkaline hydrolysis of cockroach residues subsequent to extraction under nitrogen with 80% ethanol yielded methionine and methionine sulfoxide in a ratio of 10 to 1. Additional evidence for the presence of combined methionine sulfoxide was obtained by measuring the amount of methionine sulfoxide-S35 in acid and enzymatic hydrolyzates after assimilation of Na2S3504. The data are believed to be indicative of naturally occurring peptide- or polysaccharide -bound methionine sulfoxide. Other combined amino acids were determined by ion exchange chromatography of the 5% trichloroacetic acid-insoluble cockroach residues after hydrolysis with acid or alkali. /3-Alanine, normally present only in the soluble fraction of an organism, was found in the insoluble, proteinaceous residue. 

The typical biopolymers used for the preparation of micro- and nanogels are polysaccharides (Scheme 11) cellulose (CL), chitosan (CS), hyaluronan (HA), heparin, pullulan (PuL), dextran, and gelatin - a proteinaceous polyamolytic gel obtained by partial hydrolysis of collagen. Gelatine microgels are addressed by Landfester and Musyanovych in another chapter of this issue [5] and will thus not be discussed further here. 

The mechanism of protein haze formation in wines is not fully understood. Slow denaturation of wine proteins is thought to lead to protein aggregation, flocculation into a hazy suspension and, finally, formation of visual precipitates. The importance of non-proteinaceous factors in white wine protein haze formation such as proan-thocyanidins (Koch and Sajak 1959 Waters et al. 1995a Yokotsuka et al. 1991) have been suspected for some time. Other factors such as polysaccharides, alcohol levels and pH have also been implicated (Mesquita et al. 2001 Siebert et al. 1996a). It has been observed that grape protein added to model wine does not precipitate or produce haze when heated, whereas visually obvious hazes occur when the same protein is added to a commercial wine (Pocock 2006). 

NMR spectra of humin from three major types of depositional environments, aerobic soils, peats, and marine sediments, show significant variations that delineate structural compositions. In aerobic soils, the spectra of humin show the presence of polysaccharides and aromatic structures most likely derived from the lignin of vascular plants. However, another major component of humin is one that contains paraffinic carbons and is thought to be derived from algal or microbial sources. Hydrolysis of the humin effectively removes polysaccharides, but the paraffinic structures survive, indicating that they are not proteinaceous in nature. The spectra of humin differ dramatically from that of their respective humic acids, suggesting that humin is not a clay-humic acid complex. 

Several factors lead us to believe that this paraffinic component of peat is macromolecular and nonproteinaceous. First, the peat was treated with a benzene/methanol mixture prior to isolation of humin. Thus, it is unlikely that the paraffinic structures have a significant contribution from lipids. Second, when hydrolyzed in refluxing 6N HCl, the humin lost some paraffinic carbons, but mostly its polysaccharides as demonstrated in Figure 4 which shows C NMR spectra of humin and its hydrolyzed residue. The paraffinic carbons survive the hydrolysis, demonstrating their resistance. It is unlikely that proteinaceous material would survive such a treatment as an insoluble residue. 

Like other neurodegenerative disorders, such as Alzheimer s and Parkinson s disease, prion diseases are characterized by the formation and accumulation of an aberrantly folded protein in the brain. However, a unique feature of prion diseases is their transmissibility. Prions (acronym for proteinaceous infectious particles) are mainly composed of PrPSc, polysaccharides, and lipids, but lack nucleic acids longer than 25 nucleotides, arguing against an essential role for DNA/RNA in mediating infectivity [35, 36]. Indeed, recent experiments support the protein-only hypothesis recombinant PrP expressed in and purified from bacteria and subsequently misfolded in vitro can transmit the disease [37-40]. 

The predominant mechanism of biofilm accumulation in staphylococci involves polysaccharide intercellular adhesin (PIA) [60-66], S. epidermidis strains lacking this adhesin are also regularly isolated from biomaterial-related infections, a fact which prompted a search for an alternative, PIA-independent accumulation mechanism [51, 52, 60-62, 67, 68], The responsible molecule was identified as accumulation associated protein, Aap [69-71], and there may also be a role for additional proteinaceous intercellular adhesins [52], Aap has a similar-acting homolog, SasG, in S. aureus [72], adding to the accumulating evidence that proteinaceous intercellular adhesins are also of importance in S. aureus biofilm formation and device-related infection [52, 72-74],... 

Past determinations of amino sugars have usually been carried out using standard amino-acid techniques with hydrolysis of polymeric material under the conditions applied for proteinaceous material and reporting of the total hexosamine content (e.g. Degens, 1970). Dawson and Mopper (1978b) have suggested that the conditions for hydrolysis should resemble those employed for polysaccharide material to avoid substantial destruction losses of amino sugars. 

---