(Unless otherwise cited, information for this section is from Ch. Polypeptide Chains, Procollagen and Tropocollagen Structure The backbone of proteins is the same but they are distinguished by the sequence of amino acids. 2.2) to form a polymer chain called a polypeptide. The different amino acids are linked together by a covalent peptide bond formed by a condensation reaction between the carbonyl group of one amino acid and the amino group of another amino acid (see Fig. Non-polar side chains involve only carbon and hydrogen atoms, however polar side chains contain oxygen and can frequently involve carbonyl and hydroxyl groups, amino and amide groups, or thiols (also called mercaptans, -SH). These side chains, which give each individual amino acid its unique chemical characteristics, can range from a simple hydrogen to reasonably large functional groups that can be polar or non-polar, acidic or basic, aromatic or aliphatic. 2.2: Condensation reaction of two amino acids to form a peptide bond More information on less commonly used animal skins and leathers can be found in Section 10.5.įig. Other hides, such as larger and smaller mammals, reptiles, fish, and even humans, have been experimented at one time or another for bookbinding materials, though none are found in collections in great quantities, nor do they match the traditional sources in durability and utility for their purpose. These have been selected through the years for this purpose due to the workability of the final leather product for the needs of bookbinders, but also due to their ideal size to cover a complete quarto. Calf, pig, sheep, and goat hides are the most traditional sources of bookbinding leather. While almost any hide from a vertebrate can be tanned, a select few species of animal are commonly used for bookbinding. Other materials made from animal skins, such as parchment and raw-hide, degrade if repeatedly wet (Roy Thomson 2011c). Sources of Leather Ī main attribute of leather is its resistance to purification even if kept wet. 7.7 Historic and contemporary coatings and consolidants.7.4 Consolidation, Repairing, Stabilization, Structural Treatments.7 Conservation treatments for leather bindings.6.6 Degradation of leather processing components.6.5 Degradation properties of different tans.6.1 Breakdown of the collagen structure.5.1.2 19th-20th Century Industrial Changes to Vegetable Tanning in Europe.4.2 Vegetable tannins and their reaction with collagen.2.1.1 Polypeptide Chains, Procollagen and Tropocollagen Structure.2 Chemical Composition of Untanned Hides.
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