Polyporus, enzyme

The question of the involvement of oxidative enzymes in the breakdown of cellulose has been raised periodically, but now there is definite evidence that such enzymes occur in some culture filtrates. This was established by Eriksson and his colleagues (2) when they found that concentrated cell-free filtrates of the fungi S. pulverulentum, Polyporus adustus, Myrothecium verrucaria, and T. viride solubilized cellulose at a slower rate under anaerobic than under aerobic conditions. 

In previous work, we obtained several cellulase components from culture filtrates of Irpex lacteus (Polyporus tulipiferae) or from Driselase, a commercial enzyme preparation of this fungus they behaved practically as a single protein (1,2,3). They were different in randomness of the hydrolysis of carboxymethyl cellulose (CMC), expressed as the ratio... 

Wood-degrading fungi produce a family of pyranose oxidases (EC 1.1.3.10), enzymes catalyzing the oxidation at C-2 of several aldoses. A simple and convenient conversion of D-glucose into D-arabino-hexos-2-ulose involves the use of a pyranose-2-oxidase isolated from Polyporus obtusus, which was purified and immobilized on activated CH-Sepharose 4B.446... 

We illustrate these aspects of metalloprotein dynamics at surfaces by two specific proteins. One is the two-centre bacterial di-heme protein cyt c4 from Pseudomonas stutzeri, and the other is the fungal four-centre redox enzyme laccase from Polyporus versicolor. 

In the case of Polyporus laccase, Malkin et al. (95) have differentially removed the non-blue Cu(II) from the protein. This inactivates the enzyme but leaves the intense blue color intact. The activity and original copper content can be restored by adding Cu(II) and ascorbate (95). Anions such as F" and CN" appear to inhibit by reacting with the non-blue copper (66). Fluoride, for example, appears to react exclusively with the non-blue Cu(II) since the super hyperfine lines from the fluoride nucleus appear exclusively on the non-blue Cu(II) hyperfine lines in the ESR spectrum, and the blue Cu(II) hyperfine lines remain unaltered (Figure 6) (96). Figure 6 is an ESR spectrum taken at a... 

Two other copper enzymes possess ascorbate oxidase activity, human ceruloplasm and Polyporus laccase (70,71). Ceruloplasm may function as an AA oxidase in vivo. Both ceruloplasm and laccase are 10 times less active toward AA oxidation than is ascorbate oxidase. However, the reaction is definitely enzymic, and water is produced. 

Codeine cannot be demethylated to morphine chemically.]- If it is heated with hydriodic acid no methyl iodide is evolved [169, 209-11], but the latter is evolved copiously when codeine is heated with hydriodic acid and red phosphorus [169, 211-212], the other products being intractable, varnish-like substances obtainable in the same way from morphine [213] and supposed to consist of polymers of morphine and codeine. These so-called polymers were also obtained during the action of hydrochloric and hydrobromic acids on the bases, and were the subject of an inconclusive series of investigations by Wright [169, 170, 213-14 inc.]. There is no real evidence for the existence of the polymers. Biological demethylation of codeine by various enzymes and by the glycerol extract of the mould Polyporus hispidus in nine to twelve days at 25-37° C. has been reported [225]. 

The data further suggest that Chrysosporium pruinosum, and Pent-ctllium pusillum are good sources of exo-/ -l — 4 enzyme, if one does not object to the cellobiase present. Polyporus cinnabarinus produces less exo-enzyme, but as in Trichoderma viride, it is nearly free of cellobiase. Streptomyces sp. B814 is the only organism which appears to lack exo-glucanase in its cellulase complex. 

For the concentration of enzyme solutions it is important to use methods giving the highest possible yield of enzymic activity—i.e., loss of activity should be brought to a minimum. None of the above methods will in all cases fulfill these requirements since denaturation and consequently low yield of enzymic activity are reported for all these methods. To avoid denaturation owing to precipitation as well as owing to freezedrying and evaporation, Petterson et al. (39) introduced the dextran gel concentration method of Flodin et al. (12) into cellulase research. This method was found to give essentially quantitative recovery of cellulase activity from culture solutions of Polyporus versicolor. 

Gel Filtration Technique. Cellulases were among the first proteins to be separated by the gel filtration technique. Cellulolytic enzymes from Polyporus versicolor were thus separated by Pettersson et ah (39) on Sephadex G-75 (Pharmacia Fine Chemicals, Uppsala, Sweden) and simultaneously Whitaker et ah (56) applied the same technique in studies on the cellulolytic enzymes from Myrothecium verrucaria. The gel filtration method has since been so frequently used in separation and... 

One possible explanation for these different modes of cellulose depolymerization in the same species of wood is that the cellulolytic enzyme molecules of Poria monticola are smaller than those of Polyporus versicolor and for that reason would be able to penetrate and act in regions of the fine structure of the fibers that are not accessible to those of the latter fungus. This hypothesis has led to efforts (as yet incomplete) to determine the molecular size of the cellulolytic enzyme proteins of these two organisms. Another possible explanation is that the initial dissolution of cellulose and other cell-wall polysaccharides is accomplished by catalysts that are not enzyme proteins and therefore could be substantially smaller in molecular size. Halliwell (21) has described experiments on the... 

Brown The determinations of size of the cell-wall capillaries and the cellulases of fungi indicate that the enzymes that have been isolated to date are so large that they probably can penetrate only a few cell-wall capillaries in wood and cotton. This conclusion is supported by Cowling s DP data for the action of the white-rot fungus, Polyporus versicolor, on wood (Figure 13). But it is also contradicted by the same type of data for the effect of both the brown-rot fungus, Poria monticola, on wood (Figure 13) and of Myrothecium verrucaria on mercerized cotton as shown by Selby (60). Thus we believe that the catalysts responsible for the initial depolymerization of cellulose in wood and cotton by these two... 

Pyranose-2-oxidase (E.C. 1.1.3.10), isolated from the mycelia of Polyporus obtusus. has been reported to oxidize-D-glucose and other carbohydrates at C2 to yield the 2-keto derivatives ( -8 ). The enzyme which exists as a single protein band on acrylamide gel, is a tetramer consisting of identical subunits, each of a molecular weight of 68,000 and a total molecular weight of 220,000... 

Polyporus versicolor Laccase. There are two electrophoretic forms, A and B, of fungal laccase (50—52) which otherwise seem to be identical as enzymes. 

Enzyme and source Polyporus versicolor Rhus vernicifera... 

Styrylpyrone Biosynthesis in Polyporus hispidus II. Enzymic Hydroxylation... 

Vance, C.P., E.B. Tregunna, A.M.D. Nambudiri, and G.H.N. Towers Styryl-pyrone Biosynthesis in Polyporus hispidus I. Action Spectrum and Photoregulation of Pigment and Enzyme Formation. Biochim. Biophys. Acta 343, 138 (1974). 

Cellulase from Trichoderma viride was the most effective enzyme for the synthesis of cellulose when compared with cellulases from ANL or Polyporus tulpiferae. 

As with soil, diphenol oxidases extracted from forest litter also can be fractionated to yield components essentially free of co-extracted humic compounds. A comparison of humic-free laccases (p-diphenol oxidases) purified from soil and litter extracts with those from Polyporus versicolor indicated that the former preparations were strongly electronegative and were only weakly adsorbed to humic colloids. By contrast other enzymically-active fractions from soil extracts were associated with humic compounds in complexes which were not separable by chromatography or electrophoresis. ... 

Peterson, C.A., Cowling, E.B., and Porath, J. (1963). Studies on cellulolytic enzymes. I. Isolation of a low molecular-weight cellulose from Polyporus versicolor. Biochem. Biophys. Acta. 67 1-18. 

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