Influence of chemistry in immobilization of cobra venom phospholipase A2: implications as to mechanism

João Paulo M. Ferreira, Ram Sasisekharan, Otway Louie, Robert Langer*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Phospholipase A2 from Naja naja kaouthia venom was covalently coupled onto agarose beads using two different chemistries. The effect of micellar competitive inhibitors in the coupling media was evaluated. Enzyme bound to N-hydroxysuccinimide-activated agarose, which is reactive primarily toward ϵ-amino groups, had 20% activity retention against micellar diheptanoylphosphatidylcholine (DiC7-PC). Enzyme bound through carboxylic groups, using a modification of the carbodiimide method, had 50% retention. Similar relative activities were observed, for both conjugates, in monomeric dihexanoyl-PC and in mixed micelles of Triton X-100 with dipalmitoyl-PC or dioleoylphosphatidylethanolamine. The soluble form of the enzyme showed premicellar activation against monomeric DiC7-PC, while the immobilized form showed interfacial recognition at concentrations around the critical micellar concentration. These results suggest that the enzyme activity lost upon immobilization is a result of the inherent chemical modification of the enzyme and that enzyme oligomerization and interfacial recognition are not cause-effect phenomena.

Original languageEnglish
Pages (from-to)8098-8102
Number of pages5
JournalBiochemistry
Volume32
Issue number32
DOIs
Publication statusPublished - 1993
Externally publishedYes

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