Suberization, initiation

II (Lower-index inert component) Cyclohexyl methacrylate Ethylene glycol dimethacrylate Dimethyl suberate Benzoin methyl ether 1.0 ml 0.12 ml 0.25 ml 0.06 g Monomer Crosslinking monomer Inert Initiator 1.505 -1.5 1.4326... 

Figure 4. Chromatogram of a mixture of carboxylic acids as the t-butyidimethylsilyl derivatives. GC conditions DB-1 fused-silica capillary column (30 m x 0.32 mm i.d, 0.25 pm), initially at 60 "C for 2 min, then programmed to 280 °C at 4°C/min 0.8 pi sample, injected with split ratio of 15 1 both injector and detector temperatures at 300 °C nitrogen as the carrier gas at 0.9ml/min. Peaks l = formic, 2 = acetic, 3 = propionic, 4 = isobutyric, 5 = butyric, 6 — isovaleric, 7 = valeric, 8 = caproic. 9 = enanthic, 10 = benzoic, 11= caprylic, 12 = lactic, 13 = phenylacetic, 14 = glycollic, 15 = oxalic, 16 = pelargonic. 17 = malonic, 18 = capric, 19 - succinic, 20 - methylsuccinic, 21 = undecanoic, 22 = fumaric, 23 = 5-phenylvaleric, 24 = p-aminobenzoic, 25 = lauric. 26 = mandelic, 27 = adipic, 28 = 3-methyladipic, 29 = tridecanoic, 30 = phenyllactic. 31 = hippuric, 32 = myristic, 33 = p-hydroxybenzoic, 34 = malic, 35 = suberic, 36 = pentadecanoic, 37 = vanillic, 38 = palmitic. 39 = syiingic, 40 = tartaric, 41 — margaric, 42 = a-resorcylic, 43 = p-hydroxymandelic, 44 = y-resorcylic, 45 = stearic. 46 = homogentisic, 47 = protocatechuic 48 = nonadecanoic, 49 = citric 50 = cirachidic acid. (Reproduced from Ref. 299 with permission).

The advent of combined gas chromatography/mass spectrometry has made the characterization of the aliphatic portion of the suberin polymer relatively straightforward. It is important that the initial physical isolation of the suberized tissue be done with care as this step determines the degree of suberin-enrichment in the final fraction (235, 243). Treatment of the tissue with hydrolytic enzymes, such as pectinase and cellulase, may remove a considerable portion of the cell wall carbohydrate. Strongly acidic, basic, or oxidizing conditions should be avoided to prevent chemical changes in the suberin components. The final residue is dried. 

This chapter describes the case reports of these enzyme deficiencies and the underlying biochemistry of the disorders and their associations. It is not the intention to discuss keto acidosis associated with other diseases, for example juvenile diabetes, or ketogenesis and its control which are reviewed elsewhere (Wildenhoff, 1975, 1977 McGarry and Foster, 1976 Halperin, 1977). In addition to the common occurrence of 3-hydroxybutyrate and acetoacetate in body fluids of patients with keto acidosis, secondary organic acids have been observed in urine, including adipic and suberic acids (Pettersen et aL, 1972), 3-hydroxyisovaleric acid (Landaas, 1974), 3-hydroxyisobutyric acid and 2-methyl-3-hydroxybutyric acid (Landaas, 1975). The dicarboxylic acids occur as a result of initial co-oxidation of accumulating long-chain fatty acids followed by )8-oxidation (Pettersen, 1972), and metabolites of the branched-chain amino acids occur because of inhibition of their metabolic pathways by 3-hydroxybutyrate and acetoacetate (Landaas and Jakobs, 1977). 

Fig. 14.7 Chromatogram of organic acids extracted using ethyl acetate and diethyl ether from the urine of a child with Jamaican vomiting sickness, separated as their methyl derivatives (diazomethane) on 5 per cent OV-1 using temperature programming from 70°C to 300°C at 4°C min with a 4 min initial isothermal delay. Peak identifications are 1, 3-hydroxybutyrate plus 3-hydroxyisovalerate (approx. 4 6) 2, ethylmalonate 3, methylsuccinate 4, octanoate 5, glutarate 6, adipate 7, isovalerylglycine 8, 4-octenedioate plus furandicarboxylate 9, suberate (octanedioate) 10, /i-hexanoyl-glycine 11, decenedioate 12, sebacate (decanedioate) 13, hippurate 14, n-pentadecanoate (internal standard) 15, palmitate 16, stearate. (Redrawn with modifications from Tanaka et al, 1976)...

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