On the mechanism of the glucosidic bond cleavage in the enzymic hydrolysis of starch

The hydrolysis was studied of potassium (+)-octan-2-yl sulphate by two analogous, optically stereospecific, secondary alkylsulphohydrolases purified from two detergent-degrading micro-organisms, Comamonas terrigena and Pseudomonas C12B. Polarimetry studies have shown that (+)-octan-2-yl sulphate prepared from (+)-octan-2-ol is hydrolysed by both enzymes to yield (-)-octan-2-ol. This inversion of configuration implies that the enzymes are catalysing the scission of the C-O bond of the C-O-S linkage, a type of bond scission apparently not hitherto encountered among hydrolytic enzymes acting on ester bonds. Enzymic hydrolysis of potassium (+)-octan-2-yl sulphate in the presence of H218O and analysis of hydrolysis products for the presence of 18O has confirmed that C-O bond scission (and not O-S bond scission) occurs with both enzymes.

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Bond cleavage in enzymic hydrolysis of nucleoside triphosphate to nucleoside monophosphate and inorganic pyrophosphate

Biochimica et Biophysica Acta ◽

10.1016/0006-3002(60)90244-4 ◽

1960 ◽

Vol 37 (2) ◽

pp. 344-346 ◽

Cited By ~ 4

Author(s):

Mildred Cohn

Keyword(s):

Bond Cleavage ◽

Nucleoside Triphosphate ◽

Enzymic Hydrolysis ◽

Inorganic Pyrophosphate ◽

Hydrolysis Of

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An activator stimulating the enzymic hydrolysis of sphingoglycolipids.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)33814-0 ◽

1976 ◽

Vol 251 (4) ◽

pp. 1159-1163 ◽

Cited By ~ 13

Author(s):

S C Li ◽

Y T Li

Keyword(s):

Enzymic Hydrolysis ◽

Hydrolysis Of

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Variation in Quantity of Methanol Recovered from Raisins

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/46.2.341 ◽

1963 ◽

Vol 46 (2) ◽

pp. 341-343

Author(s):

M Alice Brown ◽

James R Woodward ◽

Floyd DeEds

Keyword(s):

Methyl Ester ◽

Esterase Activity ◽

Enzymic Hydrolysis ◽

Methanol Content ◽

Naturally Occurring ◽

Pectin Esterase ◽

Hydrolysis Of

Abstract The amount of naturally occurring methanol in fruit must be known so that the quantity left as fumigation residue can be determined. In a study of methanol content of raisins, which had given inconsistent results, the raisins were subjected to different conditions of treatment immediately prior to methanol determination. Conditions that favored pectin esterase activity gave higher values for methanol content than conditions known to inactivate enzymes. Evidence was also obtained that both chemical and enzymic hydrolysis of methyl ester groups of pectic materials occur during analysis.

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Permeability of muscle capillaries to small heme-peptides. Evidence for the existence of patent transendothelial channels.

The Journal of Cell Biology ◽

10.1083/jcb.64.3.586 ◽

1975 ◽

Vol 64 (3) ◽

pp. 586-607 ◽

Cited By ~ 380

Author(s):

N Simionescu ◽

M Siminoescu ◽

G E Palade

Keyword(s):

Plasma Proteins ◽

Intercellular Junctions ◽

Rat Diaphragm ◽

Enzymic Hydrolysis ◽

Graphic Analysis ◽

Heme Peptides ◽

Future Work ◽

Hydrolysis Of ◽

Muscle Capillaries

Two heme-peptides (HP) of about 20-A diameter (heme-undecapeptide [H11P], mol wt approximately 1900 and heme-octapeptide [H8P], mol wt approximately 1550), obtained by enzymic hydrolysis of cytochrome c, were sued as probe molecules in muscle capillaries (rat diaphragm). They were localized in situ by a perixidase reaction, enhanced by the addition of imidazole to the incubation medium. Chromatography of plasma samples showed that HPs circulate predominantly as monomers for the duration of the experiments and are bound by aldehyde fixatives to plasma proteins to the extent of approximately 50% (H8P) to approximately 95% (H11P). Both tracers cross the endothelium primarily via plasmalemmal vesicles which become progressively labeled (by reaction product) from the blood front to the tissue front of the endothelium, in three successive resolvable phases. By the end of each phase the extent of labeling reaches greater than 90% of the corresponding vesicle population. Labeled vesicles appear as either isolated units or chains which form patent channels across the endothelium. The patency of these channels was checked by specimen tilting and graphic analysis of their images. No evidence was found for early or preferential marking of the intercellular junctions and spaces by reaction product. It is concluded that the channels are the most likely candidate for structural equivalents of the small pores of the capillary wall since they are continuous, water-filled passages, and are provided with one or more strictures of less than 100 A. Their frequency remains to be established by future work.

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Investigation of the products of an enzymic hydrolysis of collagens

Biochemistry ◽

10.1021/bi00840a009 ◽

1969 ◽

Vol 8 (12) ◽

pp. 4716-4723 ◽

Cited By ~ 17

Author(s):

Howard B. Bensusan

Keyword(s):

Enzymic Hydrolysis ◽

Hydrolysis Of

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Constancy of the optimum temperature of an enzyme under varying concentrations of substrate and of enzyme

Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character ◽

10.1098/rspb.1914.0073 ◽

1914 ◽

Vol 88 (602) ◽

pp. 258-262

Keyword(s):

Experimental Evidence ◽

Aspergillus Oryzae ◽

Hydrolytic Enzyme ◽

Fixed Duration ◽

Optimum Temperature ◽

Enzymic Hydrolysis ◽

Main Interest ◽

General Law ◽

The Moment ◽

Hydrolysis Of

In a recent paper a new enzymic relation is recorded. For the enzymic hydrolysis of salicin—by the enzyme which Gabriel Bertrand and the author have named salicinase —it is found that, in an action of fixed duration, the temperature of greatest activity of the ferment is always the same, whatever the dilutions of substrate and of enzyme adopted for the determination. In other words, the duration of the action being constant, the optimum temperature of the ferment is independent of the concentration both of the substrate and of the enzyme. The observation is suggestive: if true of one enzyme it may be true of all, and possibly becomes the enunciation of a general law. Herein, for the moment, lies its main interest. In the present paper further experimental evidence for this hypothesis in given, in the case of another hydrolytic enzyme, the maltase of Aspergillus oryzæ (taka-diastase).

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