Protein extract

Thaumatin. Thaumatin [53850-34-3] is a mixture of proteins extracted from the fmit of a West African plant, Thaumatococcus daniellii (Beimett) Benth. Work at Unilever showed that the aqueous extract contains two principal proteins thaumatin I and thaumatin II. Thaumatin I, mol wt 22,209, contains 207 amino acids in a single chain that is cross-linked with eight disulfide bridges. Thaumatin II has the same number of amino acids, but there are five sequence differences. Production of thaumatins via genetic engineering technology has been reported (99). 

FIG. 22-86 Process scheme for protein extraction in aqueous two-phase systems for the downstream processing of intracellular proteins, incorporating PEG and salt recycling. RepHnted from Kelly and Hatton in Stephanopoulos (ed), op. cit. adapted from Qre-oe and Kula, op. cit.]... 

Single cell protein Cells, or protein extracts, of microorganisms grown in large quantities for use as human or animal protein supplements. 

Noller, H. F., Hoffarth, V, and Zimniak, L., 1992. Unusual resistance of peptidyl transferase to protein extraction procedures. Science 256 1416-1419. 

The use of MS-MS to provide sequence information has been described [13] for the study of proteins extracted from yeast (Saccharomyces cerevisiae). The procedure was somewhat complex and consisted of the following steps ... 

Figure 5.18 Silver-stained two-dimensional gel of the proteins extracted from the yeast S. cerevisiae. From Poutanen, M., Salusjarvi, L., Ruohonen, L., Penttila, M. and KaLkM-nen, N., Rapid Commun. Mass Spectrom., 15, 1685-1692, Copyright 2001. John WUey Sons Limited. Reproduced with permission.

Fig. 1. Spectrum of potato calluses isoperoxidases (a) non-infected plants protein extract, (b) protein extract from plants, infected by P. infestans. M - protein markers.

In some cases, the anionic POs adsorbed on chitin have similar antigenic determinants, but the plants belonging to different families - and even members of the same family - could have polysaccharide-specific POs with different structures. Thus, the majority of investigated species had anionic chitin-specific peroxidises, and these isoforms from potato Solcmaceae) and horseradish Brassicaceae) formed lines of precipitation with antibodies to wheat chitin-bound PO but not to anionic isoPO (Maksimov et al., 2000). However, protein extracts from several plants of Brassicaceae, Cucurhitaceae and Fahaceae formed precipitate with both the chitin-specific and anionic PO of wheat (Fig. 3). It was foimd that the greatest homology showed in plants and formed precipitation lines with the anionic PO of wheat (Tab. 2). 

Fig. 3. The scheme of the precipitates formed by the crude protein extracts of plants of the groups monocotyledons (1-11, table 1) and dicotyledons (12-23 table 1) with antibodies against wheat chitin-binding proteins (I) and with antibodies against wheat anionic PO (H).

The mature red blood cell cannot synthesize protein. Reticulocytes are active in protein synthesis. Once reticulocytes enter the circulation, they lose their intracellular organelles (ribosomes, mitochondria, etc) within about 24 hours, becoming young red blood cells and concomitandy losing their ability to synthesize protein. Extracts of rabbit reticulocytes (obtained by injecting rabbits with a chemical—phenylhydrazine—that causes a severe hemolytic anemia, so that the red cells are almost completely replaced by reticulocytes) are widely used as an in vitro system for synthesizing proteins. Endogenous mRNAs present in these reticulocytes are destroyed by use of a nuclease, whose activity can be inhibited by addition of Ca +. The system is then pro-... 

Table 6.3 Effect of soy protein/extracts containing isoflavones on OVX-induced bone...

The psubunit has been purified from PGl by ourselves and others and is a heat stable, acidic, heavily glycosylated protein with an apparent molecular mass of 37-39 kD (19, 26). No enzymatic activity has been identified for the protein. The psubunit can be extracted from the cell walls of both green and ripe tomato fruit by high salt buffers (13, 14, 18, 19, 20), and in the latter case is associated with PG2 polypeptide(s) in the form of PGl. Purified psubunit can also associate with and convert PG2 in vitro into an isoenzyme that closely resembles PGl (13, 14, 24). Biochemical studies have shown that in vivo and in vitro formation of PGl by the association of PG2 with the p-subunit alters the biochemical and enzymic properties of the associated catalytic PG2 polypeptide including its pH optima, response to cations and thermal stability (summarized in Table 1). This later property provides a convenient assay for the levels of PGl and PG2 in total cell wall protein extracts. 

In order to choose among these various hypothesis, we followed the kinetic of secretion of the polygalacturonase in the Pg glc medium. Hence, the proteins present in daily aliquots have been acetone precipitated The protein extracts were then either placed on a reaction medium to assay for their PG activity or studied by zymogram [5],... 

Figure 1 PG activity measurement of crude protein extract of the SCPP strain grown on Pg glc medium...

Crude protein extracts and reaction media were made as described by Gainvors et al. Measurements were made on the reaction medium as described by Milner et Avigad... 

A crude protein extract has been prepared by acetone precipitation on a three days old culture supernatant of the SCPP strain on Pg glc medium. In order to estimate the effect of glucose on PG activity, these protein extracts were deposited as dots on solid Pg glc medium. 

On this medium, the protein extracts of the SCPP strain exhibited PG activity similar to the one obtained on 1% Pg medium (data not shown). Hence, it seems that at this concentration (1%) glucose does not inhibit the PG activity of the SCPP strain. 

Figure 5 Detection of PG activity of crude protein extracts of the SCPP strain in the presence of 1% glucose and varying concentrations of polygalacturonic acid.

Figure 4. Purification of PemB from E. coli K38 pGPl-2/pPME6-5 cells. Proteins were separated by urea-SDS-PAGE. Lane 1, induced cell lysate lane 2, soluble protein fraction from induced cells lane 3, membrane fraction from non-induced cells lane 4, membrane fraction from induced cells lane 5, membrane proteins not extracted by Triton X-100 lane 6, membrane proteins extracted by Triton X-100 lane 7, PemB purified by preparative electrophoresis. The molecular weight standard positions are indicated.

Figure 5. Proteins extracted from different E. chrysanthemi strains by Triton X-100 were analysed by immunoblotting with PemB-antiserum.

The activities of pectic enzymes present in cultivation medium (98 mg of protein extracted from 2.5 1 of pectin medium) were poor, not leading to the clarification of cultivation medium indicating the cleavage of pectate chains, with values 0.024 pmol/min.mg for polygalacturonase, 0.004 pmol/min.mg for exopolygalacturonase, 0.034 pmol/min.mg for pectinesterase and 0.005 pmol/min.mg for pectin lyase. The production of individual pectic enzymes was dependent on the C-source used in the cultivation medium (Tab. 1). 

An alternate approach for biomolecule recover is to employ degradable surfactants [157]. A series of nonionic surfactants has been synthesized that contain the acidic pH-degradable cyclic ketal linkage [153]. These surfactants readily form w/o-MEs when at neutral pH or higher but, the surfactants readily degrade at moderately low pH (ca. 5), releasing the encapsulated aqueous phase and its constituents. Work is ongoing to develop these surfactants in w/o-ME protein extraction processes [153]. 

Stability of several enzymes like proteases from thermophilic micro-organisms can be increased in aqueous-organic biphasic systems. Owusu and Cowan [67] observed a strong positive correlation between bacterial growth temperature, the thermostability of free protein extracts, and enzyme stability in aqueous-organic biphasic systems (Table 1). Enzymes, like other cell components (membranes, DNA, (RNA ribosomes), are adapted to withstand the environmental conditions under which the organism demonstrates optimal growth. 

Chloroform 2 OS-TrisHCl pH 7 (7/3) Protein extract from T. aquaticus Proteolysis on azocasein 9" — 67... 

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