For biochemistry Questions 2 and 3 second page please Backgr

Case 12 Production of Methanol in Ripening Fruit Focus concept in wild type and ansgenic eserase, the muryme responsible for methanol produktion is eeamined Enryme kinntics and inhibition. Mathanolisproduced fruit during the ripening process me source efthis methanol lacly methylesterase (PAE) which acts upon pectin methyl esatersto to be from the mayme Pectin that the production of them and produce mehanol other pectie PAKE activity, but this has eot been fimly establishad at devekped a transgene nomuto which at the Plant Science Department wth the wildtype was deficient activity. By comparing the behavior he trampetic the production the temamo be better understood. 1. The investigators measured PME cauryme activity peer (MG, breaker (Bri tuming mu) and red ripe (RR lomatoes. They also determined the amount by wing Western blot assay which uses specifie antibody to detect the PME prveen The aown in Figure 12 i Whe your interpretation realta? wild-type and transgenic tomatpei. (Medfied Frenkel, et a. described in I.The resul are shown in Figure 12.2. production a Compare the resuhsin Figure 12.2 with dose preserred in 12 Ismethanol kamelaled with ME activity Be methanol in the rvening fruin b What respoeable, a part, the predreien of Methanol erntent in ripening Figure 122 tamano based on in ripening fruit for the wild type and Na, the investwoors measured the ethnolcoreert the presented Fvure 123. What is Figure 12.3 EBanal content in ruening and (Based on Frenkel.

Solution

2

a. The methanol production in figure 12.2 is correlated to the PME activity in figure 12.1. The figure 12.1 gives the amount of PME activity which is greater in wild-type than transgenic, while the same is seen in 12.2 where the amount of methanol is higher in wild type than in transgenic. This clearly implies that methanol production is directly related to the PME activity.

b. The amount of active PME protein in wild type is partly responsible for the production of methanol.

3. The ethanol production in transgenic is completely opposite that of methanol production in these tomatoes. It seems to look like a compensatory mechanism where the low production of methanol in the transgenic is increasing the production of ethanol.