Hydrolysis and Analysis

Some work has been completed on reaction of proteins with nitrite followed by hydrolysis and analysis for amino acids It has been shown that 3-nitrotyrosine and 3,4-dihydroxyphenylalanine are formed from bovine serum albumin when nitrosation occurs under conditions similar to those found in the human stomach (36), Direct demonstration that nitrite reacts with protein has been made by using NaN02 with bovine serum albumin (pH 5.5, 20 C and 200 ppm nitrite). A 60% loss of the originally added nitrite was observed in one week and nearly half of the nitrite (labelled %) could be recovered from the protein. Similar work with myosin revealed that 10-20% of the incorporated label was present as 3-nitrotyro-sine (J7). 

Hydrolysis and analysis The purified and dried polymer (0.1 g) and 1 ml of aqueous HC1 (0.1 mol l 1), together with a measured amount of acetone (as internal GLC standard), was heated for 1 h at 100 °C in a sealed tube to hydrolyse the polymer. The solution was then neutralised and the ethanol content was determined by GLC by means of a calibration graph. As polymers of 4 and 5 are strongly hydrophobic and are thus hydrolysed only very slowly in water, they were hydrolysed in aqueous dioxane. 

Maillard browning will yield the constituent amino acid upon 6N HCI hydrolysis and analysis, but the Amadori amino acid moiety may be unavailable to the rat (9) since intestinal hydrolysis is less harsh than 6N HCI hydroTysis. Thus, we have a clear distinction between potential nutritional value and actual availability. 

Schmidt degradation of inandenin-10-one (63), isolated from the stem bark of Oncinotis nilida, followed by hydrolysis and analysis of the resulting mixture in a manner analogous to that described in the case of inandenin-12- and -13-one (see Scheme 11) was the basis of its structure elucidation (26). 

Preparation, fractionation, hydrolysis, and analysis of citrus processing waste. 

These findings have been applied to a stepwise sequential hydrolysis and analysis of peptides from the N-terminal end. This is comparable to the action of an aminopeptidase. With most amino acids the yield of hydrolysis varies between 30 to 50%. To improve the yield, the approach has been altered to include a solid phase support. In alkaline buffer at 60°C only the N-terminal residue remains bound to the resin support and unreactive materials can be washed and recycled (230). 

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