

precipitate was redissolved in 0.05 M potassium phosphate buffer (pH 7.0) 

 and then dialyzed overnight at 4°C against 2 changes of 4L 0.001 M 

 potassium phosphate buffer (pH 7.0). 



DEAE-cellulose Chromatography 



Crude potato PPG preparation was loaded onto a DEAE-cellulose (0.95 

 meq/g, Sigma) column (K 26/40, 40 cm length x 26 mm i.d., Pharmacia) which 

 had been equilibrated with 0.001 M potassium phosphate buffer (pH 7.0). 

 Unbound phenolic compounds and proteins were washed off using 250 mL of 

 0.001 M phosphate buffer (pH 7.0) at a flow rate of 24 mL/hr for 2 hr. 

 Elation of PPG was performed using a linear concentration (0-1.0 M) of 

 NaCl . Four-mL fractions were collected using a fraction collector (Model 

 2110, Bio-Rad), and protein profile of fractions was determined at 280 nm. 

 Fractions showing PPG activity were pooled and concentrated using an 

 Amicon stirred cell (Model 8050) fitted with a YM 10 membrane filter. 



Gel Filtration 



Partially purified enzyme preparation after DEAE-cellulose 

 chromatography was loaded onto a Sephadex G-lOO gel column (K 26/40, 

 Pharmacia) pre-equilibrated with 0.001 M potassium phosphate buffer (pH 

 7.0). Elution with 400 mL 0.001 M phosphate buffer (pH 7.0) was then 

 performed at a flow rate of 2.4 mL/hr for 15 hr. Four-mL fractions were 

 collected and protein profile of fractions was determined at 280 nm; 

 fractions showing PPG activity were pooled and concentrated using an 

 Amicon stirred cell. Concentrated samples were dialyzed at 4°C overnight 



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