88 



Table 3. Secondary Structure Estimates of Various Polyphenol Oxidases 

 (PPOs) from Far UV Circular Dichroic Spectra 











% of Secondary 



structure 





PPO 



a-h 



elix 



i3-sheet 



)8-turn 



random coil 



Mushroom 





18.3 



18.1* 



17.3 



24.8 



39.5 



Potato 





14.8 



13.1* 



34.6 



28.4 



22.2 



Lobster 





24.4 



25.1* 



26.2 



21.4 



29.9 



White shri 



mp 



29.0 



29.7* 



30.0 



11.3 



29.7 



Brown shri 



mp 



20.1 



20.0* 



22.3 



15.2 



42.4 



The circular dichroic spectra of PPO was scanned at the far UV (250 - 

 200 nm) range. Four-mL PPO (10 - 20 /xg/mL) in 0.5 mM sodium phosphate 

 buffer (pH 6.5) was analyzed at ambient temperature 



Calculated according to the formula proposed by Greenfield and Fasman 

 (1969) 



•^ -.'■ 



