Nonenzymatic degradation

The primary products from autoxidation are hydroperoxides, which are often simply referred to as peroxides. Peroxides are odorless and colorless, but are labile species that can undergo both enzymatic and nonenzymatic degradation to produce a complex array of secondary products such as aliphatic aldehydes, alcohols, ketones, and hydrocarbons. Many of these secondary oxidation products are odiferous and impart detrimental sensory attributes to the food product in question. Being able to monitor and semi-quantitate the development of peroxides by objective means (e.g., PV determination) over time is important for food scientists who want to characterize the quality of an oil or a lipid-containing food product, even though the peroxides themselves are not directly related to the actual sensory quality of the product tested. 

RNA is also nonenzymatically degraded by hydroxyl ions and, at high temperatures, by divalent cations. Hence, solutions that contain RNA should not exceed a pH value of 9 and should not be heated for too long periods of time if divalent cations are present. 

Metko, S. K., and McFeeters, R. F. (1993). Effect of the degree of methylation and pH on nonenzymatic degradation of pectin. 206th National Meeting, Am. Chem. Soc., Div. Agric. Food Chem., Chicago, IL, Abstract 112. 

Especially in the large-scale production of beer, of highest significance is not ethanol production but a balanced flavor to obtain the desired taste. One unpleasant off-flavor compound is diacetyl, which is a nonenzymatically degraded product of a-acetolactate. Diacetyl is then enzymatically converted to ace-toin and subsequently to 2,3-butanediol. The nonenzymatic-degradation step is very slow and requires long lager periods. 

Chemiluminescence resulting from the nonenzymatic degradation of the tryptophan metabolite 3-HOA (and believed to reflect degradation from Compound I to Compound IV as shown in Chart 2) is significantly increased in the urine of bladder cancer patients and in the urine of heavy tobacco smokers (285, 286). The administration of ascorbate (1 to 2 g p.o. per day) results in a significant decrease in chemiluminescence and completely prevents the formation of Compound IV even in voided urine to which 3-HOA has then been added (286). 

Others (eg, decellularized extracellular matrix, chitosan, gelatin) Synthetic Polymers (Nonenzymatic Degradation)... 

The (nonenzymatic) degradation of P3HB-3HH has not yet been tested systematically either in vitro or in vivo. Data has been reported from a short-... 

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