Activity from various sources

Jensen, R.G. 1983. Detection and determination of lipase (acylglycerol hydrolase) activity from various sources. Lipids 18 650-657. 

Oligosaccharides also occur widely as components (via glycosidic bonds) of antibiotics derived from various sources. Figure 7.20 shows the structures of a few representative carbohydrate-containing antibiotics. Some of these antibiotics also show antitumor activity. One of the most important of this type is bleomycin A2, which is used clinically against certain tumors. 

Processing equipment has standard procedures to operate and meet safety requirements. Safety information and standards are available from various sources that include the equipment suppliers, Society of Plastics Industry (SPI), and American National Standards Institute (ANSI). For the past century we have observed increasing activity on the... 

The yeast strain SCPP exhibits all of the panoply required for the degradation of pectins from various sources. This enzymatic machinery is secreted into the growth medium. Hence, we developped interest on the regulatory mechanisms controlling the synthesis of the main activity produced by the SCPP strain, i.e. the polygalacturonase. 

Proper waste management becomes increasingly important with increasing amounts of waste created by modem civilization. In cementing technology, wastes from various sources can be used in various ways. The activities may be subdivided into two main classes ... 

Altered release. Tetanus is an infectious disease caused by the bacterium Clostridium tetani. This bacterium produces a neurotoxin active on inhibitory synapses in the spinal cord. Motor neurons, which supply skeletal muscle and cause contraction, have cell bodies that lie in the spinal cord. Under normal circumstances, these motor neurons receive excitatory and inhibitory inputs from various sources. The balance of these inputs results in the appropriate degree of muscle tone or muscle contraction. Tetanus toxin prevents the release of gamma amino butyric acid (GABA), an important neurotransmitter active at these inhibitory synapses. Eliminating inhibitory inputs results in unchecked or unmodulated excitatory input to the motor neurons. The resulting uncontrolled muscle spasms initially occur in the muscles of the jaw, giving rise to the expression lockjaw. The muscle spasms eventually... 

In an effort to develop easy-to-use ketoreductase toolbox , we have surveyed the activity and enantioselectivity of a collection of ketoreductases (KRED) from various sources toward the reduction of a variety of ketones [90,91]. These studies served as a useful guideline for developing enzymatic processes for the production of optically pure chiral alcohols. For example, several chiral chlorohydrins of pharmaceutical importance were synthesized in both enantiomeric forms using the enzymes in this ketoreductase collection (Table 7.2) [92]. Further applications of this collection and other commercially available ketoreductases can be found in a recent review [9]. 

Sol id Sol utions. The aqueous concentrations of trace elements in natural waters are frequently much lower than would be expected on the basis of equilibrium solubility calculations or of supply to the water from various sources. It is often assumed that adsorption of the element on mineral surfaces is the cause for the depleted aqueous concentration of the trace element (97). However, Sposito (Chapter 11) shows that the methods commonly used to distinguish between solubility or adsorption controls are conceptually flawed. One of the important problems illustrated in Chapter 11 is the evaluation of the state of saturation of natural waters with respect to solid phases. Generally, the conclusion that a trace element is undersaturated is based on a comparison of ion activity products with known pure solid phases that contain the trace element. If a solid phase is pure, then its activity is equal to one by thermodynamic convention. However, when a trace cation is coprecipitated with another cation, the activity of the solid phase end member containing the trace cation in the coprecipitate wil 1 be less than one. If the aqueous phase is at equil ibrium with the coprecipitate, then the ion activity product wi 1 1 be 1 ess than the sol ubi 1 ity constant of the pure sol id phase containing the trace element. This condition could then lead to the conclusion that a natural water was undersaturated with respect to the pure solid phase and that the aqueous concentration of the trace cation was controlled by adsorption on mineral surfaces. While this might be true, Sposito points out that the ion activity product comparison with the solubility product does not provide any conclusive evidence as to whether an adsorption or coprecipitation process controls the aqueous concentration. 

Fig. 12 A- D. Separation of a mixture of cyctochromes C from various sources in 20 pm i. d. capillary columns. (Reprinted with permission from [78]. Copyright 2000 Elsevier). Conditions A bare capillary B unetched C18 modified capillary C,D etched C18 modified capillary, total column length 50 cm, active length 25 cm, voltage 30 kV (A,B,C) and 15 kV (D), mobile phase 60 mmol/1 a-alanine and 60 mmol/1 lactic acid pH 3.7, detection at 211 nm, pressurized injection for 2 s using vacuum...

Figure 2. Spectral properties of Cytochrome P-450s from various sources related to the BF hydroxylase activity, the inhibition of BP hydroxylase, and the extent of covalent binding of BP to DNA.

This process starts with the synthesis of novel chemical compounds. Substances with complex structures may be obtained from various sources, e.g., plants (cardiac glycosides), animal tissues (heparin), microbial cultures (penicillin G), or human cells (urokinase), or by means of gene technology (human insu-Un). As more insight is gained into structure-activity relationships, the search for new agents becomes more clearly focused. 

Current available information does not permit definitive conclusions on the nature, specificity, and mechanism of action of the protein cofactor (s) of lipoprotein lipase. It is verj difiicult to correlate the observations described above (summarized in Table 10) since the enzyme preparations used were not pure or well characterized, and were derived from various sources. For instance, two species of lipoprotein lipase have been reported to exist in rat adipose tissue (G4), and major differences between enzymes of liver and adipose tissue have been noted (G16). Also, the nature of the apoprotein preparations employed as protein cofactor (s) of lipoprotein lipase has not been clearly specified in all the studies contaminated materials may account for the spurious results observed. At present, it is not known how apoproteins such as apo Glu, apo Ala, and apo Ser could exhibit their activator or inhibitor activity on lipoprotein lipase. If these different apoproteins indeed prove to be cofactors for lipoprotein lipase, the nature of the lipid-protein specificity must be established and thus the role played by carbohydrates, since some of these apoproteins are glycoproteins. 

Qiolinesterases from various sources Quaternary heterocyclic oximes inhibit enzyme activity reversibly 127-131... 

A number of studies have examined the antioxidant activities of chitosan from various sources. Park et al. (2004a) prepared three kinds of partially deacetylated hetero-chitosans such as 90% deacetylated, 75% deacetylated, and 50% deacetylated chitosan from crab chitin, and their antioxidant properties were measured using electron spin resonance spectrometry. Park and coworkers found that their antioxidant activities were dependent on the DD, and the 90% deacetylated chitosan showed the highest free radical scavenging activities. Yen et al. (2008) also found that a sample with more amino groups at the C-2 position showed the highest antioxidant activity. Tomida et al. (2009) examined the protective effects of seven different MW chitosans on plasma protein from oxidation by peroxyl radicals. In the ability to protect plasma protein from... 

From various sources Dowden (27) has accumulated data referring to the density of electron levels in the transition metals and finds an increase from chromium to iron. The density is approximately the same from a-iron to /3-cobalt there is a sharp rise between the solid solution iron-nickel (15 85) and nickel, and a rapid fall between nickel-copper (40 60) and nickel-copper (20 80). From Equation (2), the rates of reaction can be expected to follow these trends of electron densities if positive ion formation controls the rates. On the other hand, both trends will be inversely related if the rates are controlled by negative ion formation. Where the rate is controlled by covalent bond formation, singly occupied atomic orbitals are deemed necessary at the surface to form strong bonds. In the transition metals where atomic orbitals are available, the activity dependence will be similar to that given for positive ion formation. In copper-rich alloys of the transition elements the activity will be greatly reduced, since there are no unpaired atomic d-orbitals, and for covalent bond formation only a fraction of the metallic bonding orbitals are available. 

A series of other labdane diterpenes isolated from various sources have also been reported to exhibit antimicrobial activity. Aulacocarpinolide and aulacocarpines A and B, labdane diterpenes isolated from the Cameroonian spice Aframonum aulacocarpos (Zingiberaceae), exhibited weak antibacterial activity against B. subtilis and fungus Mucur miehei [166],... 

The Fe and MoFe proteins are easily separated from each other, and proteins from various sources will cross-combine to give an active enzyme. Both proteins are very sensitive to dioxygen. 

In contrast to the claim of Szwarc and co-workers 291) that the a-methyl(styryl)-sodium active center is stable, measurements from various sources have shown 293 30l) that transformations readily occur. The dimer structure formed froma-methyl styrene and sodium is as follows ... 

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