The Effects Of Laser On Catalytic Activity Of Yeast Invertase

Objective:With the increasingly research of laser, the mechanism of biological effect has been known more and more. Because of superior properties of laser, it has been applied comprehensively in industry, agriculture, medical and health, bioengineering, and as so on. The application of Laser in biotechnology is a newly focus of research nowadays. The application of laser technology in enzyme engineering has expansive prospect, and the basic research of Laser technology in these fields has important theoretical and practical significance. This papers select yeast invertase as research object and observe the effect of laser with different parameters on its catalytic activity. Beside this, the effect mechanism of laser on yeast invertase is discussed deeply.Methods:This research is based on others work about enzyme, and it is mainly about the effect of laser with different power and exposure time on the yeast invertase activity. We studied: the effect of laser on the yeast invertase activity with different parameters such as power, exposure time, pH value, temperature, and as so on; the relationship between the change of enzyme activity of yeast invertase exposed with laser and exposure time; the enzymatic dynamics of yeast invertase treated with laser. In order to study the molecular effect mechanism of laser on enzyme, the ultraviolet absorption spectrum and ultraviolet differential spectrum are used to study the configuration and conformation of enzyme molecular.Results:In this research, we found :a) the most adaptive PH value for yeast invertase is between 4.5-5.0, and the most adaptive temperature is nearby 40℃; b) a feasible light laser can increase the activity of yeast invertase, and inversely a strong laser can decrease the activity of yeast invertase; c) while the yeast invertase is treated with 16mw/cm² laser, the enzyme activity has been increased 10%-25% if the exposure time is less than 10min, and its activity decreased if the exposure time is more than 10min; d) while the yeast invertase is treated with 240mw/cm² laser, the enzyme activity has been increased 20%-30% if the exposure time is less than 5min, and its activity decreased if the exposure time is more than 5min; e) while the yeast invertase is treated with 480mw/cm² laser, its activity will decrease with the time prolong; f) the activity of enzyme treated with adaptive intensity laser approached untreated one with the time prolong, and it is the same with untreated one after 24 hours, this means the activity change is reversible; g) the decrease of enzyme activity treated with 480mw/cm² laser changed little with time, this means the activity change is irreversible.The enzyme kinetics research of yeast invertase shows that the value of K_m and V_max changed in different extent. The reason for the enhancement of enzyme activity is mainly the increase of affinity between the enzyme and the substrate.In this research, in order to study the molecular effect mechanism of laser on enzyme, the ultraviolet absorption spectrum and ultraviolet differential spectrum are used to study the configuration and conformation of enzyme molecular. The ultraviolet absorption spectrum and ultraviolet differential spectrum analysis shows that the conformation of yeast invertase molecular changed in different extent, mainly include the change of peptide site, the change of the exposure of aromatic amino acid, and the configuration change of aperiodical coil and folding. The experiment shows that the change of spectrum is consistent with the change of enzyme activity.Conclusions:A feasible light laser can increase the activity of yeast invertase, and inversely a strong laser can decrease the activity of yeast invertase. The effect of laser on enzyme is through the change of the configuration and conformation of enzyme molecular.