Glutamine protection

The phenolic hydroxyl group of tyrosine, the imidazole moiety of histidine, and the amide groups of asparagine and glutamine are often not protected in peptide synthesis, since it is usually unnecessary. The protection of the hydroxyl group in serine and threonine (O-acetylation or O-benzylation) is not needed in the azide condensation procedure but may become important when other activation methods are used. 

S Akabori, S Sakakibara, Y Shimonishi. Protection of amide nitrogen for peptide synthesis. A novel synthesis of peptides containing C-terminal glutamine, (xanthenyl) Bull Chem Soc Jpn 34, 739, 1961. 

PG Pietta, P Cavallo, GR Marshall. 2,4-Dimethoxybenzyl as a protecting group for glutamine and asparagine in peptide synthesis. J Org Chem 36, 3966, 1971. 

Elaborate cascades initiate the clotting of blood (Chapter 12) and the action of the protective complement system (Chapter 31). Cascades considered later in the book are involved in controlling transcription (Fig. 11-13) and in the regulation of mammalian pyruvate dehydrogenase (Eq. 17-9), 3-hydroxy-3-methyl-glutaryl-CoA reductase and eicosanoids (Chapter 21), and glutamine synthetase (Chapter 24). 

The medium should be warm. Leave the filled reservoir m a warm room or incubator (this will also act as a sterility control) If glutamine concentration is critical for a hybridoma, make up medium without glutamine, and add it when changing the reservoirs. Alternatively, warm the reservoir in running warm water, taking care to protect the sterility of lid fittings... 

The IBX oxidation of protected glutamine derivatives such as Z-Leu-Phe-Gln(Trt)[CH2OH] afford linear Z-Leu-Phe-Gln(Trt)-H in 93% yield. It should be noted that oxidation of nonprotected glutamine derivatives such as Z-Leu-Phe-Gln[CH2OH] typically result in equilibration between Z-Leu-Phe-Gln-H and the predominate cyclic hemiaminal form. The oxidation of protected glutamine derivatives such as Z-Leu-Phe-Gln(Trt)[CH2OH] afford only linear Z-Leu-Phe-Gln(Trt)-H 38]... 

Normally, the induction of glutamine synthetase expression balances glutamate uptake and the increased levels of ammonia in glutamatergic areas and protects against neuronal degeneration. A decrease in glutamine synthetase expression in... 

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