Hydrolytic factor

We propose a new mechanism for cellulose degradation that is based on the formation of the cellulase complex and is compatible with the results reported in the scientific literature. An affinity factor and a hydrolytic factor are necessary for the formation of a complete cellulase which can hydrolyze native cellulose to cellobiose (Figure 2). The amount of affinity factor (xA) that combines with hydrolytic factor (yH) probably is not x = y = 1. This new mechanism does not require a separate enzyme for the formation of reactive cellulose. The natural... 

This mechanism could be unique for these anaerobic bacteria, however, the major findings reported in the literature are compatible with this proposal. Ci enzyme (3, 4) requires the addition of Cx, a hydrolytic factor, in order to effectively demonstrate activity. It may be that the Ci component is an affinity factor that binds the hydrolytic factor, Cx, to the insoluble cellulose. 

Figure 2. A new mechanism for cellulose degradation proposes the combination of affinity factor and hydrolytic factor to form a complete cellulase complex which can hydrolyze native cellulose to cellobiose...

Leatherwood Probably the classical protein-protein interaction is an antigen antibody reaction, in which two proteins interact to form a complex. And it is well known that excess concentration of one of these can interfere with the precipitin reaction. So, whenever you test affinity factors and hydrolytic factors, you must test at various levels. This would be one reason for overlooking the interaction. We have found an increase in adsorption of hydrolytic factor, by addition of it to solutions that had what we considered excess affinity factor. ... 

The SMP based syntactic foam may be used in various lightweight composite stmctures. Most of the time, the structures may be used outdoors with uncontrolled environmental attacks. The most obvious environmental attacks include ultraviolet (UV) radiation, moisture, temperature, and combinations of these single factors, such as hydrothermal attacks. Polymers are extremely sensitive to these environmental attacks due to the photophysical and photochemical effects. Often, the combination of UV radiation with oxidative and hydrolytic factors leads to more severe degradation than that from a single factor. The damage may range from mere surface discoloration to extensive loss of mechanical properties. 

Ta 1.5 X 10 2, K3 2.1 X 10 and 2.4 x and the corresponding negative logarithms are pA" 1.0, pA"2 1.8, pA"3 6.57 and pA"4 9.62. The P—O—P linkage is kinetically stable towards hydrolysis in dilute neutral solutions at room temperature and the reaction half-life can be of the order of years. Such hydrolytic breakdown of polyphosphate is of considerable importance in certain biological systems and has been much studied. Some factors which affect the rate of degradation of polyphosphates are shown in Table 12.10. 

In addition to detergency performance and feedstock economics, other factors related to the processing of these powder formulations must be considered, such as sulfonation/sulfation, crutcher slurry preparation, and spray drying. AS and AES are thermally and hydrolytically less stable than LAS. Care must be taken in spray drying to avoid decomposition and pluming problems. This may place a limitation on the levels of AS and AES in spray-dried laundry powders. 

A second group of myotoxic toxins, found almost exclusively in the venoms of cobras, are the cytotoxins (often called cobratoxins, cytolysins, cardiotoxins, or direct lytic factors). These, rather than phospholipases, are almost certainly the primary cause of muscle damage following bites by cobras. Their mechanism of action is not properly known, but it is certainly the case that their action is potentiated by the presence of phospholipases in the venom, even if the phospholipases concerned are not, themselves, myotoxic. The cytotoxins of cobra venom possess no hydrolytic activity of any kind. 

A third group of myotoxic factors are very short polypeptides, devoid of hydrolytic activity. These toxins, found in the venom of a few species of North American rattlesnakes, cause a dilatation of sarcoplasmic reticulum and can cause severe muscle damage. 

Although, as stated above, we wiU mostly focus on hydrolytic systems it is worth discussing oxidation catalysts briefly [8]. Probably the best known of these systems is exemphfied by the antitumor antibiotics belonging to the family of bleomycins (Fig. 6.1) [9]. These molecules may be included in the hst of peptide-based catalysts because of the presence of a small peptide which is involved both in the coordination to the metal ion (essential co-factor for the catalyst) and as a tether for a bisthiazole moiety that ensures interaction with DNA. It has recently been reported that bleomycins will also cleave RNA [10]. With these antibiotics DNA cleavage is known to be selective, preferentially occurring at 5 -GpC-3 and 5 -GpT-3 sequences, and results from metal-dependent oxidation [11]. Thus it is not a cleavage that occurs at the level of a P-O bond as expected for a non-hydrolytic mechanism. 

Lipases are able to catalyze many hydrolytic and esterification reactions in the presence of different substrates. The type of substrate is a key factor affecting the activity and productivity of lipase-catalyzed reactions. 

To study the factors leading to the unusual hydrolytic stability of polydimethacrylamides, we synthesized poly[N-(4-sulfophenyl)di-methacrylamide] (PSPDM) (IV). PSPDf s water soluble, in contrast to the previously studied polymers. The hydrolytic stability of PSPDM was studied in acidic, neutral, and basic aqueous solutions at 90 C and above. The results of these experiments will be described. 

An initial burst effect was observed in all in vivo studies. There are several possible factors which may cause a burst effect physically absorbed free drug, surface effects, and local tissue inflammation during the initial period of injection. It has been shown that inflammation decreases local tissue pH (15,16) and causes release of hydrolytic enzymes which would increase the hydrolysis of labile bonds, thereby increasing the release of the drug and, subsequently, increasing plasma levels of drug. 

The simplicity of the ammonolysls/amlnolysis of dlhalohalosHanes, reactions (6) and (7), made them the original method of choice for the synthesis of oligo- and polysilazanes, especially because of the analogy to the hydrolytic synthesis of polysiloxanes. The ammonolysls of dihalosilanes, reaction (6), has been found to be extremely sensitive to steric factors (6). 

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