Of enzymic hydrolysis

Simply on the basis of the normal composition of marine organisms, we would expect proteins and peptides to be normal constituents of the dissolved organic carbon in seawater. While free amino acids might be expected as products of enzymic hydrolysis of proteins, the rapid uptake of these compounds by bacteria would lead us to expect that free amino acids would normally constitute a minor part of the dissolved organic pool. This is precisely what we do find the concentration of free amino acids seldom exceeds 150 xg/l in the open ocean. It would be expected that the concentration of combined amino acids would be many times as great. There have been relatively few measurements of proteins and peptides, and most of the measurements were obtained by measuring the free amino acids before and after a hydrolysis step. Representative methods of this type have been described [245-259]. Since these methods are basically free amino acid methods, they will be discussed next in conjunction with those methods. 

The carbohydrate structure can, in principle, be unambiguously determined by use of enzymic hydrolysis. However, the method is quite laborious, and usually requires large amounts of sample. It should also be noted that, unless the samples are purified after each step, the amount of the carbanion needed for the methylation tends to become increased, and must, therefore, be assessed by means of the triphenyl-methane test in order to avoid undermethylation (see Section I). Blanks containing the enzyme used must also be analyzed in order to... 

Oligosaccharide derivatives of uridine 5 -pyrophosphate are probably present in higher plants. Cellobiose and a disaccharide composed of a glucose and an arabinose were identified among products of enzymic hydrolysis of a uridine diphosphate sugar fraction from larch wood.20... 

D-glycerol has been isolated from various red algae,377,378 rubber latex,284 turnips and rapeseed,179,294 and wheat flour.358 It is likely that this compound is a product of enzymic hydrolysis (by D-galacto-lipase)352 of DGDG. 

The economic potential of enzyme hydrolysis is therefore dependent upon the evolution of (1) cheap, readily available, large biomass sources, (2) cheap and efficient pretreatment methods, and (3) cheap and potent sources of cellulolytic enzymes. 

Table II. Fractionation Data of HEC According to Table I After One Hour of Enzymic Hydrolysis...

Fractionation Data and Distribution Analysis of HEC After One Hour of Cellulase Attack. The results of the gel chromatographic separation of HEC after one hour of enzymic hydrolysis are given in Table II. These fractionation data did not correspond to any of the distribution functions mentioned by Peebles (41) and by Tung (42). In the middle of the distribution it corresponded to the Lansing-Kraemer distribution functions, but deviations occurred at the low- and high-molecular-weight ends. 

Fractionation Data and Distribution Analysis of HEC After One Day of Cellulase Attack. In Table III, the fractionation data of HEC are given after one day of enzymic hydrolysis. As after one hour of enzymic hydrolysis, no theoretical distribution function accorded well with the fractionation data, but we evaluated the parameters by numerical analysis, using the Gauss-Laguerre method (43,44). This method has one advantage over other numerical methods, e.g., (45)—all the calculations involved can be done manually without the need of high-speed computers. 

Table V. Weight Distribution Function of HEC After 24 Hr of Enzymic Hydrolysis Calculated from the Gauss—Laguerre Numerical Computation Method Using the Four First Terms of Equation 30 with the Scaling Factors...

Macromolecule therapeutic agents tend to be more reactive than small-molecule drags under various circumstances, from sample collection to analysis. Biological and chemical transformation may occur as a result of enzyme hydrolysis, heat or... 

It should be noted that /V -carboxymethylargininc (CMA) was not found until it was realised that, unlike CML, it is unstable to acid hydrolysis. By means of enzymic hydrolysis, using peptidase and pronase E, Odani et al.35s detected 124 and 85 ng CMA ml 1 plasma (P 0.017) in Type 2 diabetics and normal subjects, respectively. An antibody to CMA has been raised.386... 

Mottram, H.R. (1999) The Application of HPLC-APCI MS to the Regiospecific Analysis of Triacylglycerols in Edible Oils and Fats. PhD thesis, Department of Chemistry, University of Bristol, UK. Movia, E. and Remoli, S. (1977) Application of enzymic hydrolysis to determine the genuineness of butter., Bollettino dei Chimici dei Laboratori Provinciali, 3, 187-192. 

Fig. 40.—Agar-diffusion pattern of the acid hydrolyzate of antigens and anti-group L Streptococci serum (S) acid hydrolyzate of group L polysaccharide (well A) native group L polysaccharide (well N), and enzyme hydrolyzate of group L polysaccharide (well E). Photograph of the paper chromatogram, showing release of carbohydrate from the polysaccharide by 1 h of acid hydrolysis, and of enzyme hydrolysis for 6-h periods.

Thus, as the first approach to kinetic studies of the action of /8-D-glu-cosiduronase toward synthetically prepared 1-O-acyl-a- and -/3-D-glu-copyranuronic acids, a reliable method that would permit monitoring of the rate of enzymic hydrolysis was needed. For this purpose, To-masic and Keglevic268 developed an analytical procedure, involving the colorimetric reaction of D-glucuronic acid with benzidine in the presence of acetic acid,269 that proved to be fully applicable to enzymic, kinetic studies performed with 1-esters of D-glucuronic acids and with D-glucosiduronic acids as the substrates. 

Theoretical Modeling of Enzymic Hydrolysis of Acetylcholine Compared to Acetylthiocholine... 

Enzymatic action can be defined on three levels operational kinetics, molecular architecture, and chemical mechanism. Operational kinetic data have given indirect information about cellulolytic enzyme mode of action along with important information useful for modeling cellulose hydrolysis by specific cellulolytic enzyme systems. These data are based on measurement of initial rates of enzyme hydrolysis with respect to purified celluloses and their water soluble derivatives over a range of concentrations of both substrate and products. The resulting kinetic patterns facilitate definition of the enzyme s mode of action, kinetic equations, and concentration based binding constants. Since these enable the enzymes action to be defined with little direct knowledge of its mechanistic basis, the rate equations obtained are referred to as operational kinetics. The rate patterns have enabled mechanisms to be inferred, and these have often coincided with more direct observations of the enzyme s action on a molecular level [2-4]. 

SSF is a process in which the production of ethanol from cellulosic materials is achieved by utilizing cellulose, cellulase, ethanol-producing microbes and nutrients in the same reactor. This process is desirable because the continuous removal of sugars by fermentative organisms alleviates end-product inhibition of enzyme hydrolysis of cellulose. The process is also simplified because only one reactor is used. The SSF process for ethanol production from cellulosic materials was reported by Blotkamp et al. [65] and was later tested on a pilot scale (for detail, see [66]). 

The mechanism of enzymic hydrolysis is still a controversial subject (Sinnott 1990 Legler 1990). There is one point of agreement in that retention is the result of two consecutive inversions, one at the time of the attachment to the enzyme, and the other when the glycosyl is transferred to the acceptor. 

The available data suggest a simple relationship between the rate of enzymic hydrolysis of succinylcholine and the duration of its action. Suppose that a patient with the usual type of plasma cholinesterase in average concentration receives a standard dose of succinylcholine which... 

Beckett and his co-workers (B14) examined the hydrolysis by purified horse serum cholinesterase of a number of analogs of butyrylcholine. The introduction of an a-methyl group into the choline moiety of the butyryl ester was found to decrease the rate of enzymic hydrolysis only slightly, whereas a drastic reduction was found for d-methyl substitution. The substitution of various functional groups into the butyryl moiety of butyrylcholine modified the affinity of the substrate for the enzyme. These results are summarized in Table 3. Since values can be assumed to be inversely proportional to affinity values, the results shown in this table indicate that j8-hydroxyl substitution increases the affinity of the substrate for the enzyme, and a,/3-unsaturation effects even greater affinity. Acetoacetylcholine has a greater affinity for the enzyme surface... 

The Oscillatory Nature of Enzymic Hydrolysis of Peptide Bonds. J. Mol. Catal. 9(4) 435-444... 

Kinetics and rate of enzymic hydrolysis of cellulose in supercritical carbon dioxide. Korean J. Chem. Eng.,... 

P. Biely and M. Vrsanska, Isolation of products of enzymic hydrolysis of xylan, Methods Carbohydr. Chem., 10 (1994) 293. 

A comparison (15) of activities of acid and enzyme catalysts on three cellulosic substrates at 50°C. shows that 100,000 times as much acid is required to bring about the same degree of hydrolysis. At the molecular level the difference is further increased because of the disparity in mol. wt. [(HC1-36, cellulase 63,000 ( 23)], so that approximately 108 HC1 molecules are required to perform the work of a single enzyme under certain conditions. This is a point strongly in favor of enzyme hydrolysis of cellulose. 

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