Free fatty acids nomenclature

Two main types in soybean are now known (Table II). The classic Theorell enzyme is LOX-1. Some confusion exists in the nomenclature, because Verhue and Francke (1972) called this form the acid enzyme (active on free fatty acids only) and Grosch et al. (1977) referred to it as the alkaline enzyme (the pH optimum is 9). The second type, LOX-2, is optimally active at pH 6.5 this is the ester enzyme of Verhue and Francke (1972), the neutral enzyme of Grosch ef al. (1977), and the b enzyme of Yamo-moto et al. (1970). The type-1 and type-2 nomenclature is now used by most workers and should be retained to avoid ambiguities. Both types are further separated into isoenzymic forms Grosch et al. (1977) refer to LOX-1,1 and LOX-1,2 isoenzymes from type 1, and LOX-2,1 and LOX-2,2 isoenzymes from type 2. Christopher et al. (1972) and Weber et al. (1974) describe a type-3 enzyme, but results (Grosch et al., 1977) indicate that this may be a mixture of isoenzymes. The major differences between types 1 and 2 are summarized in Table II. 

Production of phenol and acetone is based on liquid-phase oxidation of isopropylbenzene. Synthetic fatty acids and fatty alcohols for producing surfactants, terephthalic, adipic, and acetic acids used in producing synthetic and artificial fibers, a variety of solvents for the petroleum and coatings industries—these and other important products are obtained by liquid-phase oxidation of organic compounds. Oxidation processes comprise many parallel and sequential macroscopic and unit (or very simple) stages. The active centers in oxidative chain reactions are various free radicals, differing in structure and in reactivity, so that the nomenclature of these labile particles is constantly changing as oxidation processes are clarified by the appearance in the reaction zone of products which are also involved in the complex mechanism of these chemical conversions. 

In accordance with chemical nomenclature the sterenes can be considered a subclass of steroids as they share with these the hydrogenated cyclopentanophenan-threne carbon skeleton. Sterenes are not naturally occurring substances, but are artefacts arising from free or esterified sterols through the elimination of either the elements of water or those of a fatty acid. 

While sapwood contains very little sterol in the ester form (traces to 0.15 moles/g, dry weight basis), the amount rises strongly to about 1.1 moles/g in the inner heartwood (37, 38). Holl and Pieczonka (38) found the acid component of the esters in both cases was comprised of a number of fatty acids. In terms of the usual nomenclature (chain length number of double bonds), the fatty acid composition of the steryl esters in spruce heartwood was found to be 12 0 (10%), 14 0(12%), 16 0(20%), 16 1 (12%), 18 0(14%), 18 1 (16%), 18 2(5%), and unidentified (11%). The composition varied only slightly from this in sapwood. In both sapwood and heartwood of the spruce, the ester was a minor form of the total sterol. The ester to free sterol ratio was about 1 2 in the inner heartwood (37). Sitosterol and other sterols have also been found to exist partly in the ester form in the heartwood of angiosperms - e.g., the slippery elm (Ulmus rubra) (24). Similarly, the sterols in the bark of the western white pine (Pinus monticola) are partly (60%) esterified (13). In both heartwood and bark the steryl composition of the ester fraction approximately reflected the composition of the free sterol fraction in that sitosterol was the major component followed by its 24-methyl analogs (13, 37). A similar situation has been observed with non-woody angiosperms - e.g., Zea mays (71). 

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