Effect of cobra and viper venoms on alpha 2-macroglobulin activity in human, bovine, and goat sera.
Incubation of human serum with cobra or viper venoms (10 micrograms/0.1 ml serum) caused negligible decrease in total protease inhibitory activity whereas alpha 2-macroglobulin activity was reduced by 67.0-82.0% in 16 hr. The action of venoms on MG activity was time dependent. Human alpha 2-macroglobulin activity was reduced to a much greater extent than goat or bovine factors by the venoms. While 25 micrograms venoms/0.1 ml serum caused 60-100% inhibition of human alpha 2-macroglobulin activity, the bovine factor was not affected under similar conditions. Goat alpha 2-macroglobulin was affected to the extent of 0-20%. Evidence is provided to show that venom proteases generate endogenous proteases in situ in human plasma or serum which in turn bind to alpha 2-macroglobulin. The venom-mediated action was abolished by prior dialysis of the serum or its dilution. Ethylenediaminetetraacetate at 10(-3) M concentration also blocked the reaction. While phenylmethylsulfonyl fluoride had no effect, pepstatin in the concentration range 10(-2) to 10(-3) M caused partial inhibition of the venom-mediated inhibition of alpha 2-macroglobulin activity in human serum.
Sujatha
S
S
Department of Biochemistry, Kasturba Medical College, Karnataka, India.
Jacob
R T
RT
Pattabiraman
T N
TN
D000818:Animals; D002417:Cattle; D004546:Elapid Venoms / Q000494:pharmacology*; D006041:Goats; D006801:Humans; D066298:In Vitro Techniques; D011480:Protease Inhibitors / Q000378:metabolism; D013997:Time Factors; D014757:Viper Venoms / Q000494:pharmacology*; D000511:alpha-Macroglobulins / Q000378:metabolism*
D004546:Elapid Venoms; D011480:Protease Inhibitors; D014757:Viper Venoms; D000511:alpha-Macroglobulins