Pichit TosukhowongBhinyo PanijpanPintip RuenwongsaUtaiwan Thamrongyouth2025-02-032025-02-03198720251987Thesis (M.Sc. (Biochemistry))--Mahidol University, 1987https://repository.li.mahidol.ac.th/handle/20.500.14594/103357Biochemistry (Mahidol university 1987)Urate oxidase is useful in the enzymatic determination of uric acid. The source of this enzyme in various plants was investigated. Urate oxidase in various vegetable was assayed by using the decrease in absorbance of uric acid method and it was detected in two kinds of vegetables. High level of urate degrading activity was found in soybean seedlings, and a small amount in yam bean. By analysing the products of enzyme reaction, the urate degrading enzyme in soybean seedlings was not dependent on urate, but it was dependent on cadaverine. This result showed that urate degrading activity in soybean was not a urate oxidase but it was a diamine oxidase. Diamine oxidase has several potential applications, especially in the determination of diamines. The only commercial source of diamine oxidase is pea diamine oxidase. The soybean diamine oxidase was therefore studied in comparison to pea diamine oxidase. Soybean and pea diamine oxidase were partially purified by ammonium sulfate precipitation, DEAE-cellulose chromatography and Sephadex G-200 gel filtration. The specific activity of soybean diamine oxidase obtained was about 40 U/mg and 8 U/mg for pea diamine oxidase. Both enzyme have a similar size about 180,000 D as determined by Sephadex G-200 column chromatography. The enzyme activity for various substrates analoques were compared. Cadaverine was the compound most rapidly oxidized by soybean diamine oxidase. Putrescine was the compound most rapidly oxidized by pea diamine oxidase. Soybean and pea diamine oxidases both were strongly inhibited by diethyldithiocarbamate. ?,?-dipyridyl and phenylhydrazine. Apparent K(,m) values for cadaverine of soybean diamine oxidase was 46.5 ?M and 77.3 ?M for pea diamine oxidase. Both soybean and pea diamine oxidase was stable at temperature from O to 45 degree C. The optimum temperature of soybean diamine oxidase was about 45 degree C and that for pea diamine oxidase was 40 degree C. The pH optimum was about pH 7.5 for both soybean and pea diamine oxidase.vii, 83 leaves : ill.application/pdfengผลงานนี้เป็นลิขสิทธิ์ของมหาวิทยาลัยมหิดล ขอสงวนไว้สำหรับเพื่อการศึกษาเท่านั้น ต้องอ้างอิงแหล่งที่มา ห้ามดัดแปลงเนื้อหา และห้ามนำไปใช้เพื่อการค้าAmine Oxidase (Copper-Containing)CadaverineDiaminesEnzymesPeasPlantsSoybeansUrate OxidaseMaster ThesisMahidol University