| Summary: | 碩士 === 國立臺灣大學 === 藥學研究所 === 86 === Superoxide dismutase (SODs)，a family of metallo-enzymes，catalyze
the dismutation of potentially harmful superoxide free radical
O2.- to molecular oxygen and hydrogen peroxide , and is considered
a major enzymatic defense against O2.- radicals . The superoxide
dismutase has been detected in a wide range of living things , and
classified into three distinct essential types : Fe-SODs , Mn-SODs
and CuZn-SODs .
The unstable superoxide radical O2.- is generated within aerobic
biological systems during both enzymatic and nonenzymatic oxidations
, and SOD has been implicated an essential defense against the
potential toxicity of oxygen .
According to the literature, three molecular forms of SOD , such
as CuZn-SODs, Fe-SODs and Mn-SODs were characterized in leaves from
various Citrus plants . However , it has never been found SOD in peels.
The Chinese drug "Chen-pi (陳皮)" was prepared from the peels of various
Citrus species and has been used as an anti-inflammatory medicine for
bronchitis , mammitis and anti-tussive. There is a close correlation
between SOD and anti-inflammation.
Therefore , the characterization of SOD in peels from various Citrus
species: C. sinensis(橙), C. grandis (柚), C. chachiensis(柑), C.
limonia(檸檬), C. junos(柳丁) and C.reticulata(橘)were carried out in
this study. Based on their sensitivity to H2O2 and CN- , it
could be distinguished the three types of SODs in the protein
extract ,e.g. Citrus sinensis contains CuZn-SOD and Mn-SOD ; others
contain Mn-SOD and Fe-SOD. By nitro blue tetrazolium (NBT) assay ,
the total SOD specific activity was determined as below：
417.1±32.3、50.9±11.9、338.3±64.4、225.8±6.1、767.1±65.1 and
160±24.4 mUnit/ug , respectively . The molecular weight of these
SODs were estimated as compared with protein standards
(page54,table 6). Furthermore, it was also found that the SOD
specific activity decrease with storage period increase in the
freezer .the usefulness of the enzyme is worth further studying
in the future.
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