Acid Phosphatase And Its Interaction With Surfactants, SDS, SDBS And CTMAB

Enzyme is important to the function of being and nearly associated with the metabolism of it. Phosphatase exists extensively in the body of beings, for example, the low life-form coliform and barm and the structure and body fluid of high life-form. Phosphatase catalyses the hydrolysis of phosphorous compounds and is one of important enzymes of phosphorous metabolism. Now the surfactants are widely applied and they may affect environment and be one of the factors of environmental pollution. The surfactants can affect the activity and structure of phosphatase, consequently influence its function and physical metabolism.The effects of anionic surfactants SDBS and SDS, cationic surfactant CTMAB on acid phosphatase (ACPase) were studied detailedly on account of above reasons.Firstly the basal property of ACPase and effects of general denaturants on it were studied. The results showed that the catalysis of ACPase from wheat germ had optimal pH(5.5) and optimal temperature(40C); Hg2+,Cu2+,Zn2+ and urea could not only inhibit the activity of ACPase but also destroy its structure partly or completely. The results of chemical modification of functional groups indicated that arginine, tryptophan, lysine and histidine group were essential for the activity of ACPase.SDBS, SDS and CTMAB were added to two different soils. Initially SDBS and SDS inhibited the activity of soil ACPase. With the extending of incubation time, they activated ACPase. Compared to SDBS and SDS, CTMAB had litter effect on soil ACPase and it activated the activity of soil ACPase basically. The effect of surfactant on soil ACPase is nearly associated with the organic matter and fertility of soil. Commonly, the activity of ACPase in soil which has more organic matter is higher and the soil can protect the activity of ACPase more effectively.A majority of enzymes exist in soil in form of immobile enzymes. The ACPase from wheat germ was studied as effector in order to reveal the effect mechanisms of surfactant and soil ACPase. And the conformational changes of ACPase in solution were measured by fluorescence and differential UV-absorption spectrum. The resultsindicated that SDBS and SDS changed the microenvironment of tryptophan and tyrosine groups of enzyme. Namely, surfactants changed the active site of enzyme and consequently they inhibited the activity of enzyme. Conformation changes in solution studies indicated that SDBS, SDS and CTMAB probably influenced the activity of enzyme by combining with the active site of free and immobile soil ACPase and changing the conformation of it.