Protein, acetylated isolation

After digestion of the modified protein and isolation of the radioactive peptides, the specific activities of these peptides and of the acetylated amino acid standard are determined. This procedure is repeated at several pH s... 

In about 1936, sialic acid was discovered by Blix, who found it to be a component of submaxillary-gland proteins, and who described many of its properties. However, little notice was taken of this work at the time it was published. In 1941, Klenk, who was working on glycolipids of the brain, described a compound, later shown to be a methyl glycoside of sialic acid, that had been obtained by treatment of a lipid fraction with 5% methanolic hydrogen chloride at 105°. In 1954, Klenk and Faillard reported the first isolation of pure N-acetyl-neuraminic acid from animal sources. 

A number of ribosomal proteins contain modihed amino acids at the N terminus or at other positions of the protein chain (Table IV). The N termini of three proteins (S5, S18, and L7) are acetylated, thus they cannot be subjected successfully to manual or automatic Edman degradation because of their blocked N termini. Mutants have been isolated in... 

This enzyme [EC 1.2.99.2], also known as acetyl-CoA synthase, catalyzes the reaction of carbon monoxide with water and an acceptor to produce carbon dioxide and the reduced acceptor. The cofactors of this enzyme include nickel and zinc ions as well as non-heme iron. Methyl viologen can act as the acceptor substrate. The enzyme is isolated from Clostridium sp. Interestingly, it also catalyzes an exchange reaction of carbon between Cl of acetyl-CoA and carbon monoxide. The protein participates in the synthesis of acetyl-CoA from carbon dioxide and hydrogen in the organisms. 

As outlined before, it is beUeved that the TPX epoxyketone chain acts as an isosteric substrate mimic for the natural N-acetyl lysine. In 1996, Schreiber et al. exploited the irreversible binding nature of TPX in an affinity matrix by immobiUzing modified TPX onto an activated agarose support [44]. hi this way a mammahan histone deacetylase protein (HDACl) was isolated and characterized for the first time. 

In subsequent years, much evidence has been adduced to support this mechanism. Alkaline phosphatase and, by analogy, other serine enzymes, are directly phosphorylated on serine serine phosphate is not an artifact (Kennedy and Koshland, 1957). In the presence of nitrophenyl acetate, chymotrypsin is acetylated on serine, and the resulting acetylchymotrypsin has been isolated (Balls and Aldrich, 1955 Balls and Wood, 1956). Similarly, the action of p-nitrophenyl pivalate gave rise to pivaloyl chymotrypsin, which could be crystallized (Balls et al., 1957). Neurath and workers showed that acetylchymotrypsin is hydrolyzed at pH 5.5, but that it is reversibly denatured by 8 M urea the denatured derivative is inert to hydrolysis and even to hydroxylamine, whereas the renatured protein, obtained by... 

The extent of succinylation and acetylation was determined by the trinitrobenzenesulfonic acid (TNBS) method as described by Hall et al. (31) Protein (5 mg) isolated from chemically modified and control soy flour in 0.8 ml of aqueous solution was added to 1 ml of 4% NaHCOg, followed by addition of 0.2 ml of 2,4,6-trinitrobenzenesulfonic acid (12.5 mg/ml). The reaction mixture was incubated at 4O C for 2 hr, and 3.5 ml of 36% HCl was added. The tubes were stoppered and kept at 110 C for 4 hr. After cooling to room temperature (24 C), volume of solution was made up to 10 ml with distilled water, and contents were extracted twice with anhydrous diethyl ether. 

Eugene Kennedy and Albert Lehninger showed in 1948 that, in eulcaiyotes, the entire set of reactions of the citric acid cycle takes place in mitochondria. Isolated mitochondria were found to contain not only all the enzymes and coenzymes required for the citric acid cycle, but also all the enzymes and proteins necessaiy for the last stage of respiration—electron transfer and ATP synthesis by oxidative phosphoiylation. As we shall see in later chapters, mitochondria also contain the enzymes for the oxidation of fatty acids and some amino acids to acetyl-CoA, and the oxidative degradation of other amino acids to a-ketoglutarate, succinyl-CoA, or oxaloacetate. Thus, in nonphotosynthetic eulcaiyotes, the mitochondrion is the site of most energy-yielding... 

Chitin is classically a linear polymer of /3-d-(1 - 4)-linked 2-acetamido-2-deoxy-D-glucosyl residues. However, after comparing chitin isolated from different sources, it became evident that substantial variations in solubility, molecular weight, acetyl values, and specific rotation occur among samples. It would appear that chitin is not a single, polymeric entity, but rather, a family of closely related products derived from natural chitin-protein complexes.209... 

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