help with skate enzymes

[Rui Martins]

i've been attempting to run enzyme cellulose acetate gels on skate tissue 
for the last 6 weeks--very unsuccessfully i might add.  does anyone have 
any advice to give?  we've played with temperature, pHs, buffers, 
orientations, polarities, times...and we're simply at our wits' end.  we 
recently rean a rainbow trout using the same method (reversing the 
polarity--as we were advised to do in the literature) and it worked 
beautifully.  any ideas? i'd appreciate them.  (here or at 
rmartins at uoguelph.ca)