Modelling the effects of ageing time of starch on the enzymatic activity of three amylolytic enzymes.
The effect of increasing ageing time (t) of starch on the activity of three amylolytic enzymes (Termamyl, San Super, and BAN) was investigated. Although all the enzymatic reactions follow michaelian kinetics, v(max) decreased significantly (P < 0.05) and K(M) increased (although not always significantly) with the increase in t. The conformational changes produced in the starch chains as a consequence of the ageing seemed to affect negatively the diffusivity of the starch to the active site of the enzymes and the release of the reaction products to the medium. A similar effect was observed when the enzymatic reactions were carried out with unaged starches supplemented with different concentrations of gelatine [G]. The inhibition in the amylolytic activities was best mathematically described by using three modified forms of the Michaelis-Menten model, which included a term to consider, respectively, the linear, exponential, and hyperbolic inhibitory effects of t and [G].
Department of Analytical and Food Chemistry, Food Science and Technology Faculty, University of Vigo, Ourense Campus, 32004 Ourense, Spain. nelsonpg@uvigo.es
Nelson P
NP
Guerra
Lorenzo
L
Pastrana Castro
D004798:Enzymes / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D008956:Models, Chemical; D013213:Starch / Q000737:chemistry*
D004798:Enzymes; D013213:Starch