ScienceAsia 32 Supplement 1 (2006): 037-042 |doi: 10.2306/scienceasia1513-1874.2006.32(s1).037

Chemical Modification of Lysine and Histidine Residues in Gracilaria tenuistipitata Bromoperoxidase: Effect on Stability and Activity

Jirasak Kongkiattikajorn^a*, Pintip Ruenwongsa^b and Bhinyo Panijpan^b

 
ABSTRACT: Bromoperoxidase (BPO) from the Thai red seaweed Gracilaria tenuistipitata Chang et Xia has been chemically modified with iodoacetamide under defined experimental conditions yielding derivatives of native bromoperoxidase with enhanced catalytic activity. It has been shown that this modified reagent reacts with the -amino groups of 15 out of a total of 46 lysine residues and 9 from a total of 16 histidine residues of bromoperoxidase. Results obtained on kinetic parameters before and after modification are discussed in terms of their contributions to the mechanism of irreversible thermoinactivation and activity enhancement. The results presented in this study indicate that bromoperoxidase may acquire some new and useful characteristics related to stability and activity upon modification of specific side chains in their primary structures involving specific amino acids in this enzyme.

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a School of Bioresources and Technology, King Mongkut’ s University of Technology Thonburi, Thailand.
b Department of Biochemistry, Mahidol University, Thailand.

* Corresponding author, E-mail: jirasak.kon@kmutt.ac.th