Abstract
Determination of Kinetic Parameters of Microbial Dipeptidyl Peptidase IV
Dipeptidyl peptidase IV (EC 3.4.14.5; DPPIV) is an important enzyme that has role for regulation of tissue and organ systems and been investigated for neurological, immunological and gastroenterological aspects. DPPIV is expressed as regulator enzyme by mammalian, plant, insect and microbial cells. Recently, commercial DPPIV enzyme production has increased via using as dietary supplement for people who suffer from deficiency of digestion enzyme, autism, celiac and Asperger syndrome. Although fungal resources which are expressing extracellular enzyme were preferred to produce DPPIV, production of DPPIV is recently performed by bacteria; because, productivity values are generally higher in bacteria than fungus. In this study, Lactococcus lactis spp. lactis (L. lactis) was used as an enzyme producer microorganism. L. lactis expresses endo– and exo-peptidases which DPPIV is one of them to hydrolyze casein. Intracelluler DPPIV enzyme was purified after the production and some of kinetic properties were investigated for enzyme characterization. Results indicated that the optimum pH and temperature were 8.0 and 40°C with Gly-Pro-pNa as the substrate, respectively. Purified enzyme showed a strong preference for Gly-Pro-pNA as substrate. The enzyme was inhibited by Hg+2, Zn+2, Ca+2, Fe+2 and Mg+2, respectively. It is important and serin protease inhibitor PMSF. The enzyme was strongly inhibited by Diprotin A. Inhibition of the enzyme by jelatin and phenylmethylsulfonyl fluoride (PMSF) were found as similar, and no inhibition was detected with ethylenediaminetatraacetic acid (EDTA).
Keywords
Dipeptidyl Peptidase IV, enzyme inhibition, enzyme kinetic, Lactococcus lactis spp. lactis
