Enzymes carbohydrases

Heparins and heparinoids form complexes with proteins and bases, and as shown by the ability to produce metachromasia with submicro quantities are very effective complexing agents in trace amounts. Hence, these substances in trace amounts affect many biological agents such as enzymes, etc. When heparin or a heparinoid is injected in animal or man, an enzyme appears in the blood plasma, lipoprotein lipase. When an oil emulsion is incubated with varying amounts of blood plasma obtained after injection of heparin, the oil is cleared. The heparin has caused the release of this enzyme from tissues to the blood. Heparin and heparinoids have a pronounced action on many enzymes - proteolytic enzymes, carbohydrases, etc. and may inhibit, activate. 

Portions (50 mU MCA-hydrolsing activity) of purified CinnAE were incubated at 37°C with SBP (10 mg), both in the presence and absence of other carbohydrases, in 100 mM MOPS (pH 6.0) in a final volume of 1 mL. Incubations containing boiled enzyme were performed as controls. Reactions were terminated by boiling (3 min) and the amount of free ferulic acid determined using a method described previously for de-starched wheat bran [18]. The total amount of alkali-extractable ferulic acid present in the SBP was 0.87% [5]. 

In nature, amylases act hand in hand with each other and with other carbohydrases in bringing about the rapid breakdown of starches and glycogens to sugars which can be utilized readily by the living cell. Much important and practical information has been accumulated by the use of extracts and crude precipitates in which more or less natural mixtures of enzymes have been studied in the laboratory. However, the... 

It is important to note that no evidence of maltase activity was found in the amylase preparations even when the highest concentrations used in these comparisons were allowed to react for twenty-four hours with one per cent maltose under the conditions for the hydrolysis of starch. Similarly, no evidence was obtained for the presence of any other contaminating or extraneous carbohydrases in the amylase preparations. Partial inactivation of the amylase under a number of different conditions failed to give any evidence of selective inactivation such as might be expected if more than one enzyme were present. The substrates used for measuring the activity of the partially inactivated amylase were starch and starch hydrolyzates that had already been extensively (58) J. Blom, Agnete Bak and B. Braae, Z. physiol. Chem., 250, 104 (1937). 

A recent study, however, has shown that aminopeptidase activity is present on the surface of porcine buccal mucosa, and that various aminopeptidase inhibitors, including amastatin and sodium deoxycholate, reduce the mucosal surface degradation of the aminopeptidase substrate, leucine-enkephalin [149], Since the peptidases are present on the surface of the buccal mucosa, they may act as a significant barrier to the permeability of compounds which are substrates for the enzyme. In addition to proteolytic enzymes, there exist some esterases, oxidases, and reductases originating from buccal epithelial cells, as well as phosphatases and carbohydrases present in saliva [154], all of which may potentially be involved in the metabolism of topically applied compounds. 

The difficulties attendant on the isolation of pure enzymes of known specificity is a major barrier to their routine use for the structural analysis of polysaccharides. As the specificities are separated and as the action patterns of carbohydrases become better defined, these enzymes may be expected to play an important and vital role in the investigation of the structure of synthetic polysaccharides containing ordered sequences of sugar residues. Conversely, it may be anticipated that synthetic carbohydrate polymers of known structure will aid in studies of the specificity requirements of purified enzymes. 

As research has progressed in this area, many systems have been shown to follow a similar behaviour. Such phenomena are important in the production of enzymes and metabolites. In industrial applications, these very important control mechanisms usually have to be bypassed for the reliable generation of high concentrations of enzymes. Good examples may be seen in carbohydrase production systems,... 

Complex carbohydrates such as starch are anotlier group of condensation polymers. Enzymes such as amylase, a carbohydrase, can Itydrolyse complex carbohydrates to simple sugars winch can be represented as... 

According to Bhat (2000), the world market in 1995 for industrial enzymes was above 1.0 billion U. S. dollars, where 20% was attributed to cellulase, hemicellulase, and pectinase sales. This market increased to around 1.6 billion in 2000 and 2.0 billion in 2005. Presently, it is estimated at 4 billion U. S. dollars, 60% of which is for industrial enzymes (Costa et al., 2007). The world demand for enzymes is expected to rise 6.5% annually, to nearly 5.1 billion U. S. dollars, in 2009, according to the market researcher Freedonia Group (www.fredoniagroup.com). In this context, hydrolases represent 75% of the industrial enzymes, and carbohydrases are the second largest group of industrial enzymes. On a worldwide level, industrial enzymes are produced in Europe (60%) the balance is from the U. S. A. and Japan (40%). 

Pectic enzymes occur as endogenous enzymes in higher plants they are also added as processing aids during processing. Technical pectinase preparations are mainly derived from Aspergillus nicer and contain next to pectic enzymes many other carbohydrases. 

Pullulanase is an extracellular enzyme of Aerobacter aerogenes that causes essentially quantitative hydrolysis of pullulan to maltotriose. The enzyme is readily prepared in a crude form that is free from other carbohydrases, and is important in structural studies because it debranches amylopectin and glycogen. When the A. aerogenes is grown in continuous culture, the enzyme is bound to the cells, but it can be released by detergents, and purified by ion-exchange chromatography. This purified enzyme has been crystallized. ... 

We will discuss first whether there is an absolutely definite limit of action for all amylases. In the case of the action of /5-amylase on starch and on a-dextrins this question seems to be settled, but in the case of the malt a-amylase the answer is less certain. But certainly the action of the malt amylase practically stops at a certain limit. There is, however, almost always a very slow further action. It is possible that this slow saccharification of the limit dextrins is due not to the amylases but to other carbohydrases which have no action on starch but which are capable of attacking products with short chains. Under all circumstances it must be kept in mind that when in an experiment the saccharification for practical purposes has stopped and the limit dextrins have been isolated, this does not necessarily mean that the limit dextrins will not be further attacked by the enzyme used. But the velocity of this action is certainly very small compared with the velocity of the action on starch. Thus, it must be admitted that experiments involving the isolation of the limit dextrins after the action of a certain amylase on starch are in most cases not strictly reproducible. TJie total yield and chain length distribution of limit dextrins may vary, but their general character is not affected. If a limit dextrin produced by a certain amylase is treated with the same enzyme for a very long time, it is very often transformed to another limit dextrin of lower molecular weight with concomi-... 

Limit Dextrins from Barley Starch. In one experiment, barley starch paste was treated with malt extract, in a second experiment with purified malt amylase (Table XVII). The purified enzyme has yielded limit dextrins with chain lengths greater than those given by the malt extract, possibly because certain carbohydrases capable of attacking the limit dextrins have been removed in the purification or because of a lower stability of the purified enzyme. 

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