Effect Of Intestinal Enviroment Of Goat And Yellow Cattle On β-Carotene-15, 15'-Oxygenase Activity

Effect of intestinal environmental factors of goat and yellow cattle on the activity of -carotene-15,15'-oxygenase( P COX) were studied in this thesis.Firstly, Km of P COX was determined .that of goat and yellow cattle was 14.41 u M and 1.31 M, respectively. Then, effect of BHT , Fe2+, Lutein , bile salt and free fat acid (FFA) on P COX acitivy of goat and yellow cattle were studied..In the first experiment, results showed :1) Fe2+ promoted the cleavage of P C between the concentration of 0.5mM and 2 mM .The most suitable concentration was 1mM. 2) BHT inhibited the activity of P COX. The amount of retinol was half of that of the control group in the content of 5 M BHT. 3) Similarly, the cleavage of P C was prevented by Lutein in the incubation mixture.In the second experiment, the effect of free fat acid (FFA) on the P COX activity was studied. Results showed: 1) linoleic acid, linolenic acid and oleic acid improved the activity of P COX of both goat and yellow cattle. 2) There was a possive relativity between the concentration of FFA and P COX activity.The third experiment's results showed: 1) all kinds of bile salts promoted the cleavage of P C for goat. The sequence from high to low was : glycodeoxycholic acid > glycocholic acid > glycochenodexycholic acid > deoxycholyltaurine sodium>taurocholic acid. 2) Compared to the control group, the activity of P COX of yellow cattle was obviously inhibited by glycodeoxycholic acid , glycocholic acid and glycochenodexycholic acid; however, the activity was promoted by deoxycholyltaurine sodium and taurocholic acid. 3) deoxycholyltaurine sodium and taurocholic acid increased the amount of retinol in the concentration of between 4 mM - 10mM for both goat and yellow cattle. But the most suitable concentration was 8 mM.The last experiment's result showed: 1) For goat, FFA was dominant in the effect of intestinal environmental factors on P COX activity, then bile salt and Lutein ,the last one was Fe2+. 2) For yellow cattle ,bile salt was dominant in the effect of intestinalenvironmental factors on P COX activity, then Lutein and FFA, the last one was Fe2+.