Enzyme extraction from

Electrolyte leakage due to the action of endogenous enzymes. Extracts from tub ... 

Assays of soil enzyme activities are usually carried out in soil slurries, since efficiencies of enzyme extraction from soil and purification are still low (49). Such assays, under these conditions, will only give a measure of potential rather than actual activities moreover, they constitute integrated measures of activity as enzymes come from a variety of sources and are in several states in the soil (50). Enzyme activities may vary substantially with the season according to the synthesis, release into soil, and persistence of plant, animal, and microbial enzymes (57). 

Fan YYD (2003) Preliminary study of an enzyme extracted from AlcaUgenes sp. Strain YF11 capable of degrading pesticides. Bull Environ Contam Toxicol 70 367-371... 

SpribiUe R, Forkmann G (1984) Conversion of dihydroflavonols to flavonols with enzyme extracts from flower buds of Matthiola incana. Z Naturforsch 39C 714-719... 

Stotz G, Forkmann G (1982) Hydroxylation of the B-ring of flavonoids in the 3 - and 5 -position with enzyme extracts from the flowers of Verbena hybrida. Z Natuforsch 37C 19-23... 

Fig. 7. Chemical structure of azumamide A-E and activity against the crude enzyme extract from K562 cells. ...

In vitro studies were conducted with enzymes extracted from peanut (7), pea (. ), and onion (9). The enzymes were fractionated by ammonium sulfate precipitation, dialyzed, and stored frozen until used. The enzymes were assayed for various activities as described In the Results and Discussion. 

The following spectrophotometric methods are conceptually related to the POV however, they are intended for other purposes. HPLC-UVD at 234 nm was applied to detect lipid hydroperoxides, obtained in a set of experiments for assessing the effectiveness of lipoxygenase enzymes extracted from various microorganisms. The absorbance. A, measured at three different wavelengths is linearly correlated to the concentrations in xM units of lipid hydroperoxides, Clh, 7-oxocholesterol, Cqc and dienals, Cde according to the set of simultaneous equations 60. This method was used to track the Cu(II)-induced oxidation of LDL" °. 

The first evidence that supplementation of exogenous ADA may be helpful in SCID patients came from the 1975 report of Potmar et al. [8], demonstrating that addition of bovine-intestinal ADA or human-erythrocyte ADA to cultures of lymphocytes of a SCID patient restored their ability to proliferate when stimulated with mitogens. The ability to respond to mitogens is an indicator of immune function restoration. Therapeutic use of enzyme extracted from calf tissue revealed that this form of ADA has a short half-life. 

Enzyme replacement is a chronic therapy that typically requires administration every week or two. Antibody response is a concern because immune reactions could produce signihcant morbidity, and mortality in rare cases. According to the manufacturer, about 15% of patients treated to date have developed IgG antibodies to Cerezyme within the hrst year, and most often within six months of initiating therapy. After 12 months of therapy, patients who do not seroconvert are less likely to develop antibodies. Nearly half of patients with detectable IgG antibodies are reported to experience some symptoms of hypersensitivity. Whether exposure of mannose on the enzyme (for targeting the enzyme to leukocytes) plays a role in eliciting or enhancing antibody response to the enzyme is not known and probably worth investigating. About 13% of patients on Ceredase also produce antibody response to the enzyme extracted from placenta. 

Dignum M, Kerler J, Verpoorte R (2001b) Alpha-glucosidase and peroxidase stability in crude enzyme extracts from green beans of Vanilla planifilolia Andrews. Phytochem Anal 12 174-179... 

Li YH, Sim ZH, Zao LQ, Xu Y (2005) Bioconversion of isoeugenol into vanillin by crude enzyme extracted from soybean. Appl Biochem Biotechnol 125 1-10... 

Fig. 25.1 The three pathways for the preparation of natural flavours. The first two involve the extraction of the flavour or precursors from natural sources. The precursors can then be converted to the natural flavour by enzymes extracted from plants or microorganisms. The last method is the de novo synthesis of the flavour by microorganisms growing on simple substrates such as glucose and sucrose...

Biotransformation is the conversion of a compound into the product using living plant cells or enzymes extracted from plants [42,43]. This is the third option for using plant cell cultures for flavour production. Some examples are given in Table 25.3, but at present the yields are still low. 

The use of plant cells or enzymes extracted from the cells for the biotransformation of exogenous substances offers another method for producing flavours. This would be useful when compounds are not found in cell suspensions. Many studies have been carried out on the biotransformation of xenobiotics or pharmaceuticals by plant cell culture [43, 50]. 

Many enzymes extracted from higher plants have been tried for clotting cheese milk (Burnett 1976), however, attempts to use them have been unsuccessful. Most plant proteases are strongly proteolytic and cause extensive digestion of the curd, which has resulted in reduced yields, bitter flavors, and pasty-bodied cheese. 

Crude enzyme extracts from the white-rot fungus Oudemansiella mucida oxidize D-glucose to D-pryt/zro-hexos-2,3-diulose (265) via o-arabino-hexos-2-ulose. Compound 265 was identified by NMR and mass spectroscopy of the N, N- di p he n y 1 h y dr a zo ne derivatives 491... 

Fig. 7 Chemo-enzymatic formation of tetrahydroalstonine from tryptamine and secologanin by an enzyme extract from engineered E. coli harbouring a dual vector expressing both, STR1 and SG cDNAs from R. serpentina cell suspension cultures followed by chemical reduction. Due to simultaneous expression of STR1 and SG cDNAs, the intermediate strictosidine does not accumulate...

Ziegelhoffer et al. (15) tested the stability of the apoplast-targeted Elcd in transgenic tobacco plants. In their study, the apoplast-targeted Elcd enzyme extracted from tobacco plants, along with the purified microbial Elcd, was subjected to different temperatures (60-90°C) for 10 min. Both enzymes showed similar high thermal stability throughout the experiment. Their results showed that at 60°C up to 95%, at 70°C up to 90%, at 80°C up to 80%, and at 90°C up to 40% of the enzymes activity was retained. However, as seen in Fig. 4, our heat stability test showed sur-... 

Hyaluronidase is an enzyme extracted from mammalian testes (e,g.t bovine iestes) and capable of hydrolyzing mucopolysaccharides nf the hyaluronic add type. It contains not lea than 3001.U. ofhyahiroaidase activity per milligram, calculated with reference to die dried suhstance. It may contain a suitable stabilizer. 

Table V. Release of soluble degradation products from yeast RNA during incubation with raw enzyme extract from potatoes at different temperatures and pH values (degradation products in pM x 10 3/rn ). From Dumelin Solms (8).

The PA caffeine is produced from xanthosine via three distinct N-methylations (Fig.7.5).87 89 Partially purified enzyme extracts from tea (Camellia senensis) and coffee (Coffea arabica) were shown to exhibit all three activities, suggesting either that the A-methyltransferase steps in caffeine biosynthesis are catalyzed by a single enzyme, or by multiple enzymes with similar properties.90 However, a specific A-methyltransferase purified from coffee was active only toward 7-methylxanthine and theobromine91 An A-methyltransferase catalyzing the methylation of methylxanthines and designated caffeine synthase (CS) was purified from tea.92 CS catalyzes two consecutive methylations involved in the conversion of 7-methylxanthine to caffeine, but is inactive toward xanthosine, indicating that the first methylation proceeds via a different enzyme. Heterologous expression of the CS cDNA showed that the enzyme was active toward 7-methylxanthine, paraxanthine,... 

Figure 6.2 An example of the phylogenetic tree derived for peroxidase enzymes extracted from various plants. The digits refer to the particular plant species for which the DNA sequencing was carried out [1].

---