Macerans amylase

Thus, Freudenberg concluded that the cyclodextrins are not preformed in starch, but that their formation is made possible by the helicity of the starch chain. Freudenberg s hypotheses concerning the starch structure (that is, the amylose fraction) and the Bacillus macerans amylase mechanism have been confirmed by X-ray crystallography and chromatographic techniques. ... 

In the authors experiments, the cycloamyloses by very prolonged action of the enzyme did vanish with the production of maltose. It is not clear if this is an action of the Bacillus macerans amylase or of another enzyme present in the bacillus. After a very long time the yield of fermentable sugar was about 60% of the starch. 

The action of /8-amylase on starch partially degraded by the Bacillus macerans amylase was determined (Table XXVII). The amount of maltose decreases with decreasing degree of polymerization. When the... 

Substrates for Production of Schardinger Dextrins by B. macerans Amylase. 224... 

Fig. 9.—Radioautograph of paper chromatogram showing radioactive Schardinger dextrins produced from radioactive glycogen by B. macerans amylase. Small amounts of linear oligosaccharides together with unreacted residues from the glycogen were removed by beta amylase action and converted to maltose and maltotriose.

Considerable effort has been spent on working out methods for the production of B. macerans amylase, and although high yields have been obtained in some cases, there is need for improvement in this re.spect. 

The usual laboratory method for obtaining B. macerans amylase is to culture the organism on an autoclaved potato or oatmeal medium in the presence of calcium carbonate at 37-45° for 2-4 weeks. The culture fluid (filtrate or centrifugate) contains enzyme which can be stored as such,... 

Fig. 17-—Iodine test for Schardinger dextrins. Microscopic appearance typical of the early stage of the decomposition of starch by B. macerans amylase. Under higher power the crystals are seen to be blue hexagons.

Fio. 20.—Assay of B. macerans amylase based upon 50% transmission of light at 660 uin through the dextrin-iodine solution after 5, 10, and 20 minutes. ... 

A method adapted to quantitative measurement of B. macerans amylase activity depends on the decrease in viscosity of a standard starch substrate during enzymolysis. Since other amylases also cause viscosity drops this method lacks specificity, but it may be useful in some cases. -... 

A method capable of adaptation to B. macerans amylase assay is based upon the optical rotational shifts observed during coupling reactions (see p. 22f) and Fig. 21). ... 

A mixture of 0.25 g. of a-dextrin and 0.05 g. of u-glucose is treated with B. macerans amylase in a total volume of 25 ml. The optical rotation is measured from time to... 

Practically all workers in the field have noted that different starchy substrates differ in their behavior with B. macerans amylase, both as regards the total yields of Schardinger dextrins and also with respect to the relative proportions of alpha and beta dextrins. 

The possibility that B. macerans amylase is capable of effecting ring closure with short amylose chains has been tested by Levine. Using mal-... 

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