Enzymes 2-Octenal

The enzyme catalysed epoxidation of alpha-olefins like 1-octene with oxygen to the optically active epoxide provides an interesting example of a four-phase system (de Bont et al., 1983). The hold-up of the organic phase may be 2-4 % and the presence of biosurface active agents leads to the creation of a large liquid-liquid interfacial area the liquid droplet size becomes smaller than the gas-liquid diffusion film thickness. 

It is noteworthy that, in contrast to mammalian systems, the majority of bacterial strains exhibited sufficient activity even when the cells were grown under non-optimized conditions. Since enzyme induction is still a largely empirical task, cells were grown on standard media in the absence of inducers. Furthermore, all attempts to induce epoxide hydrolase activity in Pseudomonas aeruginosa NCIMB 9571 and Pseudomonas oleovorans ATCC 29347 by growing the cells on an alkane (decane) or alkene (1-octene) as the sole carbon source failed [27]. 

The existence of a cytosolic epoxide hydrolase was first indicated by its ability to hydrolyze analogs of insect juvenile hormone not readily hydrolyzed by microsomal epoxide hydrolase. Subsequent studies demonstrated a unique cytosolic enzyme catalytically and structurally distinct from the microsomal enzyme. It appears probable that the cytosolic enzyme is peroxisomal in origin. Both enzymes are broadly nonspecific and have many substrates in common. It is clear, however, that many substrates hydrolyzed well by cytosolic epoxide hydrolase are hydrolyzed poorly by microsomal epoxide hydrolase and vice versa. For example, l-(4 -ethylphenoxy)-3,7-dimethy I -6,7-epoxy-//7//i,v-2-octene, a substituted geranyl epoxide insect juvenile hormone mimic, is hydrolyzed 10 times more rapidly by the cytosolic enzyme than by the microsomal one. In any series, such as the substituted styrene oxides, the trans configuration is hydrolyzed more rapidly by the cytosolic epoxide hydrolase than is the cis isomer. At the same time, it should remembered that in this and other series,... 

With mushroom homogenate, a process for the production of (R)-l-octen-3-ol (Fig. 3.3) has been developed [13]. To improve the yield of (R)-l-octen-3-ol, a lipid rich in linoleic acid and the commercially available enzyme lipase may be added to the mushroom homogenate. 

CIC Vitamin C (300 mg/100 g fmit), citric acid and malic acid are responsible for the clean acidic taste of the fresh fruit. A high enzyme activity of a lipoxygenase produces high amounts of (E)-2-hexenal, hexanal and (E)-2-hexenol, all fruity green notes, characteristic of green apples. The cut surfaces develop at prolonged standing 2-heptenal, 2,4-nonadienal and l-octen-3-one, responsible for stale, fatty odour. Methyl butyrate and ethyl butyrate impart the ripe, fruity, estery, fresh, juicy impression. 

It has been established that in many edible mushrooms such as Agaricus campestris and Agaricus bisporus, the C8-compounds are formed enzymically during the oxidation of linoleic acid (16-20). In the present study, the identification of l-octen-3-ol and 2-octen-l-ol as major C8-compounds in macerated fresh Shiitake mushrooms suggested a similar biosynthetic origin. The amount of C8-compounds (primarily l-octen-3-ol and 2-octen-l-ol) in the blanched (97°C, 8 min) or the hot-air dried (commercial process)... 

Tressl et al. (16) proposed a enzymic pathway of C8-compounds from linoleic acid. Enzymes involved in the pathway are lipoxygenase, hydroperoxide lyase and oxidoreductase. The 13- and 9-hydroperoxides of linoleic acid were proposed as the products of lipoxygenase action and the precursors of C8-compounds. Enzymic reduction of l-octen-3-one to l-octen-3-ol in Aqaricus bisporus has been demonstrated (21), which is similar to the reaction of oxidoreductase mentioned by Tressl et al. (16). Wurzenberger and... 

Grosch W. and Wurzenberger M. (1985) Enzymic formation of l-octen-3-ol in mushrooms. Weurman 4th Flav. Res. 

Ethylene, propene, and octene, all linear olefins, only detectably alkylate pyrrole ring D of the prosthetic heme of the phenobarbital-inducible rat liver P450 enzymes (Figure 7.15), but heme alkylation by the more globular olefins 2-isopropyl-4-pentenamide and 2,2-diethyl-4-pentenamide is less regiospecific ... 

Fig. 8.35. Enzyme reduction of l-octen-3-one to 3-oc-tanone by Saccharomyces cerevisiae...

The enzymic formation of aldehydes, ketones, alcohols, and oxoacids (from linoleic and linolenic acids) on disruption of plant tissues is an important biosynthetic pathway by which fruit and vegetable volatiles are formed. Some examples are (E)-2-hexenal ("leaf aldehyde") and ( )-3-hexenol ("leaf alcohol") in tea (E)-2-hexenal in apples (E,Z)-2,6-nonadienal ("violet Teaf aldehyde") and (E)-2-nonenal in cucumber ( Z)-5-nonenal in musk melon (Z,Z) -3,6-nonadienol in water melon, and 1-octen-3-ol ("mushroom alcohol") in certain edible mushrooms and Fungi. The enzyme system is highly substrate specific to a (Z,Z)-1,4-pentadiene system (like lipoxygenase) splitting the >C = C< double bond at the W - 6 and/or W - 9 position. Therefore linoleic-, linolenic-, and arachidonic acids are natural substrates. It seems to be a common principle in leaves, fruits, vegetables, and basidiomycetes. 

All 0X0- and hydroxy acids were characterized for the first time as enzymic degradation products from linoleic acid. The major components 1-octen-3-ol and 1,5-octadien-3-ol were optically active. This was proved by formation of an ester with an optically active acid and capillary separation. The methods used will be published in the near future (Tressl and Engel 1981). These results indicate a highly specific enzyme-system in Agaricus campestris catalyzing the conversion of linoleic acid into (-)-1-octen-3-ol and 10-hydroxydecanoic acid resp. into ( )-2-octen-1-ol and 9-hydroxydecanoic acid. As demonstrated in Table VI linolenic acid is transformed into the corresponding C8 Components containing two C = C bonds. 

Figure 10 summarizes some results of the lipid-oxidation system in basldlomycetes, leaves, fruits, vegetables, and cereals. It can be seen that there is a development with evolution and differentiation. The enzyme system is highly substrate specific to a (Z,Z)-1,4-pentadiene system converting linoleic- and linolenic acids into carbonyls and oxoacids which may undergo further isomerization (E3) and/or reduction (E4). Some of the components formed are very potent aromatics, pheromones, and wound hormones. Basidio-mycetes and Fungi produce (-)-1-octen-3-ol as their sensorial principle. 9-Oxodecanoic acid is known as queen substance and is the sex pheromone of honey bees. 

Epoxide hydratase is primarily microsomal (James and Little 1980) and present in highest activity in hepatopancreas (Table 20) the enzyme is also found in other tissues, viz. in nmol min mg microsomal protein, green gland 0.1 to 5.7 gill 0.4 to 3.5 egg masses 0.1 to 3.9 (James etal. 1979a see Table 20 for species and substrates). The activity was similar in hepatopancreas of male and female C. sapidus , and had a pH optimum of 6.6 to 12 (substrate BaP 4,5-oxide) and 7 to 7.8 (styrene oxide and octene oxide) H. americanus), and, for styrene oxide, a temperature optimum of 45 to 50 P. argus) or 35 to 40 (C. sapidus) and an... 

Linoleic acid is a dominant fatty acid in mushrooms (see p287). Enzymes in the mushroom break it down and l-octen-3-ol is one... 

Recently, the SMO from Rhodococcus sp. ST-5 and ST-10 have been applied to catalyze the epoxidation of 1-hexene and 1-octene to the corresponding (S)-epoxides with up to 99% ee [58]. For 1-hexene, the activity was comparable to that acquired with the native substrate styrene [58], but the initial conversion rate was four times lower than styrene [92]. The excellent (S)-stereoselectivity is a complementary to the (R)-selectivity of majority of the enzymes involved in the asymmetric epoxidation of aliphatic alkenes. 

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