Linear proteins

Sompuram SR, Vani K, Hafer LJ, et al. Antibodies immunoreactive with formalin-fixed tissue antigens recognize linear protein epitopes. Am. I. Clin. Pathol. 2006 125 82-90. 

Fig. 1. The four types of linear protein domain relationships. They have been ordered by degree of complexity in a manner analogous to the Chomsky finite automaton language hierarchy. Only the first three have been identified in nature thus far. This is no doubt that, in the fourth case, multiple simultaneous mutations would be required. If the linear order of the amino acid sequence is viewed as generated by a finite automaton, there is an equivalence with the Chomsky hierarchy. 

Oral absorption of levetiracetam is nearly complete it is rapid and unaffected by food, with peak plasma concentrations in 1.3 hours. Kinetics are linear. Protein binding is less than 10%. The plasma half-life is 6-8 hours and may be longer in the elderly. Two thirds of the drug is excreted unchanged in the urine, and no active metabolites have been found. 

In nature, thread-like polymeric material fulfils an essential structural role. Plant life is built mainly from cellulose fibres. Animal life is built from linear protein material such as collagen in skin, sinew and bone, myosin in muscle and keratin in nails and hair. The coiled polypeptide chains of the so-called globular proteins which circulate in the body fluids are folded up to give corpuscular particles. 

To avoid the difficulties of translucency and the irregularities in the structure of the paper, reflection photometry has been proposed (K17, L4, R6, R7, S14, T3). Originally a linear protein/dye relationship was claimed for reflectance measurements (L4) but soon the same error as for translucency readings was found (Fig. 37). A theoretical account... 

Peptides have long been recognized as important flavor compounds in processed foods. The taste of peptides per se is veil known in cheeses (1), meat (2), hydrolyzed vegetable protein including soy products T3), cocoa (A, 5) and to a lesser extent in roasted malt (6), corn steep liquor (7) and aged sake (8). Structurally, food peptides can occur as linear protein fragments (1-3, 5), cyclic dimers (diketopiperazines, DKPs)(A, 6-81 and cyclic trimers (7). 

Non-linear protein binding of valproate can result in disproportionate increases in unbound drug adverse effects can then result when dosage adjustments are based solely on measurement of total valproate serum concentrations in patients with hjrpoalbuminemia. 

FIGURE 1-31 DNA to RNA to protein. Linear sequences of deoxyribonucleotides in DNA, arranged into units known as genes, are transcribed into ribonucleic acid (RNA) molecules with complementary ribonucleotide sequences. The RNA sequences are then translated into linear protein chains, which fold into their native three-dimensional shapes, often aided by molecular chaperones. Individual proteins commonly associate with other proteins to form supramolecular complexes, stabilized by numerous weak interactions. 

The design of linear protein sequences that are not mere copies of natural compounds has to address the major inherent problem of polypeptide chain folding, i.e., the competition between intra- and intermolecular interactions. To overcome such uncertainties, amphiphilic polypeptides were also attached as neighboring side chains to a carrier molecule or template assembly protein (TASP), namely ACCKAPGKAKCNH. Both central (LysAlaLys = KAK) units have all NH2 groups on the same side of the ring, and one can assemble... 

Tlie protein-folding enigma, the shaping of linear protein-sequences into three-dimensional stmctures, is addiessed both experimentally and by computational methods. 

Pharmacokinetics dose-dependent because of non-linear protein-bondage ... 

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