Biological Starting Material

Originally antibodies were obtained by injecting an antigen to an animal to induce an immune response leading to the secretion of specific antibody molecules. This is still an important method for generating antibodies. When antibodies are intentionally induced in humans by vaccination and the blood is collected from volunteer donors, then these sera are called hyperimmune sera. 

Each additional immunization and each individual animal creates a different pattern of specific antibodies. This peculiar situation may limit the continuity of long-term studies using only polyclonal antibodies as diagnostic tools. On the other hand, polyclonal antibodies are almost not susceptible to single mutations of antigens, and therefore they are more proper in all cases when a more broadly specificity is desired. In practice the question is not if monoclonal antibodies are better than polyclonal antibodies. Requirements and problems in diagnosis of livestock diseases are individually different and it will be advantageous and helpful if both types of antibodies are available and combinatorial use is possible. 

Compared with the generation, such as the laborious steps in screening, subcloning, and the in vitro production, monoclonal antibodies require more technology and equipment and therefore cause higher costs and consume more time. 

TABLE I Molecular Properties of Antibodies and Related Solid-Phase Separation Methods 

Main properties of antibodies Related chromatographic separation Type of interaction on solid phase 

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Specifications for biological starting materials may need additional documentation on the source, origin, method of manufacture and controls applied, particularly microbiological controls. 

The biological starting material contains other proteins, DNA and RNA, either from the medium or secreted by the host cell, and endotoxins. Endogenous and exogenous viruses, mycoplasma, bacteria, and proteins responsible for transmissible degenerative encephalopathies (TDE) must also to be considered as serious contaminants present in biological starting material. 

Biopolymers are polymers generated from renewable natural sources, often biodegradable and nontoxic. They can be produced by biological systems (i.e., microorganisms, plants, and animals), or chemically modified from biological starting materials (e.g., cellulose, starch, natural fats, or oils). 

Although chemical techniques can be used to modify the properties of biopolymers in order to expand their range of applications, this is not the unique way to improve biopolymer performance. There are different methods to transform biopolymers in sources of structural polymers that may supplant traditional commodity plastics, such as genetic manipulation of some plant species, polymerization of biological starting materials, or the creation of new gene sequences that can lead to novel protein polymers through the application of recombinant DNA methods. However, only biopolymer physical/chemical modifications will be discussed in this chapter. 

Biological materials used as sources of feedstocks are usually complex mixtures, which make separation of desired materials difficult. However, some compensation is made for that disadvantage in that in some biological starting materials nature has done much of the synthesis of the final product. Most biomass materials are partially oxidized, as is the case with carbohydrates, which contain approximately one oxygen atom per carbon atom (compared to petroleum hydrocarbons that have no oxygen). This can avoid expensive, sometimes difficult oxidation steps, which may involve potentially hazardous reagents and conditions. The complexity of biomass sources can make the separation and isolation of desired constituents relatively difficult. 

The discussion of acylation reactions in this chapter is focused on fluonnated carboxylic acid derivatives and their use to build up new fluorine-containing molecules of a general preparative interest Fifteen years ago, fluonnated carboxylic acids and their derivatives were used mainly for technical applications [/] Since then, an ever growing interest for selectively fluonnated molecules for biological applications [2, 3, 4, 5] has challenged many chemists to use bulk chemicals such as tnfluoroacetic acid and chlorodifluoroacetic acid as starting materials for the solution of the inherent synthetic problems [d, 7,, 9]... 

The preparation of adamantane from readily available starting materials (Chapter 13, Section I) has opened the door to a study of its many substitution products, both from a chemical and a biological point of view (/). Adamantylamine hydrochloride for example, has been found to exhibit antiviral activity. Presented below are several procedures for the preparation of adamantane derivatives. 

Carboxylic acids, RC02H, occupy a central place among carbonyl compounds. Not only are they valuable in themselves, they also serve as starting materials for preparing numerous acyl derivatives such as acid chlorides, esters, amides, and thioesters. In addition, carboxylic acids are present in the majority of biological pathways. We ll look both at acids and at their close relatives, nitriles (RC=N), in this chapter and at acyl derivatives in the next chapter. 

Alkylamines have a variety of applications in the chemical industry as starting materials for the preparation of insecticides and pharmaceuticals. Labetalol, for instance, a so-called /3-blocker used for the treatment of hi h blood pressure, is prepared by SN2 reaction of an epoxide with a primary amine. The substance marketed for drug use is a mixture of all four possible stereoisomers, but the biological activity derives primarily from the (R,R) isomer. 

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