Interaction Of Phospholipase A2 From Yipera Russelli Venom With Aristolochic Acid: A Circular Dichroism Study

Interaction of phospholipase A, from
nPe+n ncrnlli venom with aristolochic acid : a drcalar dichrohm :tudy. Ta~rr23, 939-945.
1987 . - The interaction of aristolochic add, an alkaloid from ArittoJochto spaia, with
Phospholipese As (PLC from yJpena n~t1G venom was followed by circular dichroism
measurements. Aristolochic acid is a non-competitive inhibitor of PLA,. The binding of
ariuolochic acid to PLA, induces an extrindc CD band at 320 nm. The association oonatant was
determined by following the intensity of the artrindc CD band. Aristolochic add forma a 1 : 1
complex with P1:.A with an assodation count X, of S.4 x 10' M-' and a Oibb's free energy
d~ange (AO°) for the reac'on of -S.1 tal/mole. The values of assodation constant and 0G°
suggest that the iateractioa is weak. Binding of aiistobchic acid causes a change in the se~dary
structure of the protdn which is characterized by an inaease in the apparent content of a-helix,
without any detectable change in the tertiary struexure of PLA,.