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M Nummi

Publications and source records attributed to M Nummi.

14 recordsLinked to original sources
PubMed1985

A new appraisal of the endoglucanases of the fungus Trichoderma reesei.

The properties and enzymic activity of endoglucanases (EC 3.2.1.4) of the fungus Trichoderma reesei were studied by means of immunological methods and by using polyglycosidic substrates. Endoglucanases exist in the culture liquid as a series of immunologically related components. The most active endoglucanase component has an Mr of 43 000 and pI value of 4.0. The most abundant components have a value of pI about 5.0, an Mr of 56 000-67 000 and specific activity only one-fifth of that of the pI-4.0 component. During purification and storage the endoglucanases are spontaneously modified; the relative proportion of components having greater Mr values, more alkaline pI values and lower specific activities is increased. The hexose content of the endoglucanase components is 2-7%. Endoglucanases hydrolyse soluble beta-1,4 glycans. The enzymes described here differ from endoglucanase preparations described previously in not showing activity towards insoluble substrates. The role of endoglucanases in wood hydrolysis is consequently limited to the stage where wood constituents are already in soluble form.

Cellulase↗
PubMed1985

Measurement of xylanase activity with insoluble xylan substrate.

Insoluble xylan was prepared from ground birch (Betula pubescens) pulp by alkali extraction and precipitation with ethanol. The only sugar detected after acid hydrolysis of the preparation was xylose. The insoluble xylan was used as substrate in a nephelometric assay to determine the xylanase (EC 3.2.1.8, 1,4-beta-D-xylan xylanohydrolase and EC 3.2.1.37, 1,4-beta-D-xylan xylohydrolase) activities of Aspergillus and Trichoderma enzymes. The nephelometric method is reliable in evaluating xylanase hydrolysis of insoluble xylan.

Aspergillus↗
PubMed1985

Combination of three techniques for the study of complex enzyme mixtures: polyacrylamide gel electrophoresis, immunodiffusion and detection of enzymatic activity.

A technique is presented in which two different separation methods are combined. The first separation is carried out in polyacrylamide gel electrophoresis, which is then followed by immunodiffusion in agarose against appropriate antisera. Soluble and insoluble macromolecular carbohydrates were used as substrates in the detection of the various enzymatic activities. These three methods in combination can provide new information on enzymatically active proteins in mixtures, such as isoenzymes, and multiple forms varying in molecular size.

Electrophoresis, Polyacrylamide Gel↗
PubMed1983

Cellobiohydrolase from Trichoderma reesei.

A 1,4-beta-D-glucan cellobiohydrolase (EC 3.2.1.91) was purified from the culture liquid of Trichoderma reesei by using biospecific sorption on amorphous cellulose and immunoaffinity chromatography. A single protein band in polyacrylamide-gel electrophoresis and one arc in immunoelectrophoresis corresponded to the enzyme activity. The Mr was 65 000. The pI was 4.2-3.6. The purified enzyme contained about 10% hexose. The enzyme differs from previously described cellobiohydrolases in being more effective in the hydrolysis of cellulose.

Cellulose 1,4-beta-Cellobiosidase↗
PubMed1979

Incidence of zearalenol (Fusarium mycotoxin) in animal feed.

Zearalenol, the reduction product of zearalenone produced by Fusarium roseum growing in cereals, was found for the first time naturally occurring in oats and corn. This metabolite is three to four times more active estrogenically than zearalenone.

Animal Feed↗