Enzymatic hydrolyzates, chemical analysis

An excellent review on protein hydrolysis for amino acid composition analysis has been published by Eountoulakis and Lahm [190], Hydrolysis can be performed by either chemical (under either acidic or basic conditions) or enzymatic means. The acidic hydrolysis itself can be carried out in a liquid or a gas-phase mode. The conventional acid hydrolysis uses 6M HCl for 20-24 h at 110°C under vacuum [200], In these conditions, asparagine and glutamine are completely hydrolyzed to aspartic acid and glutamic acid, respectively. Tryptophan is completely destroyed (particularly in the presence of high concentrations of carbohydrate), while cysteine and sometimes methionine are partially oxidized. Tyrosine, serine, and threonine are partially destroyed or hydrolyzed and correction factors have to be applied for precise quantification [190,201],... 

Fig. 3. Chemical and enzymatic treatment to reduce the size and complexity of the GPI anchor for mass spectrometric analysis. PIPLC removed the acylalkylglycerol lipids, then endoproteinase Lys C cut the amino acid chain after Lys220, giving the C-terminal peptide attached to the phosphorylated glycan. Incubation with 50% aqueous HF was used to hydrolyze the phosphodiester bonds and to release the glycan and the peptide, which were separated by RP-HPLC and analyzed independently.

The biofunctionalization of PET with the aim to increase hydrophilicity of the hydrophobic polyester surfaee has wide-ranging applications from textile finishing to technical and medical fields. Among the biocatalysts with PET-hydrolyzing activity that have been reported so far, several have shown promising results for the biofunctionalization of PET as an alternative to presently used chemical or physical methods. However, an enzymatic treatment of PET materials requires highly active bioeatalysts and short treatment times to become industrially viable. Analysis of the effieieney of PET hydrolysis performed with biocatalysts at... 

HPLC is the most common technique applied to the determination of the chemical composition of lecithin. Normal phase HPLC is convenient for the determination of the major constituents (i.e., phosphatidylcholine, phosphatidylethanolamine, etc), as described in Chapter 7. P NMR is also suitable for this analysis, as discussed in Chapter 14. The biochemical literature contains many enzymatic methods, mainly for specific determination of phosphatidylcholine and its hydrolysis product, choline (32). For instance, phosphatidylcholine can be hydrolyzed by phospholipase C to a diacylglycerol and the phosphate ester of choline, which itself can be hydrolyzed by alkaline phosphatase to form choline and phosphate ion. Alternatively, action of phospholipase D on phosphatidylcholine yields phosphatidic acid and choline. These methods are not applied to analysis of the commercial lecithin used as a surfactant. 

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