13c nmr spectroscopy of 90 % -enriched [ [ 3-13c ] ala1 ] phospholipases a2 shows the pk values of the alpha-nh3+ groups of porcine enzyme , porcine isoenzyme , bovine enzyme , and equine enzyme to be 8.4 , 8.8 , 8.9 , and 8.8 , respectively .
C0022173
isoenzyme
C0014442
enzyme