摘要
无壳葫芦籽黄化苗中苯丙氨酸解氨酶(PAL)经硫酸铵分级分离、亲和层析纯化,PAGE、SDS—PAGE和Sephadex G—200凝胶过滤表明为单一蛋白带或单一蛋白峰。用SephadexG—200凝胶过滤法测得无壳葫芦籽PAL的全酶分子量为280 000,SDS—PAGE测得其亚基分子量为74 000,推测无壳葫芦籽PAL均由分子量相同的四个亚基构成。测得无壳葫芦籽PAL的最适pH为8.5,酸碱稳定区域在碱侧,最适温度为45℃,具有一定的耐热性,以L—苯丙氨酸为底物测得Km为2.6×10^(-5)M(pH8.8,40℃)。
PAL has been isolated and purified to homogeneity by ammoniumsulphate fractionation, DEAE-cellulose-52 chromatography and affinitychromatography on L-phenylalanine-Sepharose 4B column. The puritywas identified by polyacrylamide gel electrophoresis in the presence andabsence of sodium dodecyl sulphate (SDS). The molecular weight ofcucurbita pepo linn. PAL was estimated to be approximately 280000dalton by sephadex G-200 gel filtration. Electrophoresis on sodium dodecylsulphate-p-lyacrylamide gel yielded a single stained protein band whichcorresponded to a subunit weight of 74000. Thus, these findings showedthat PAL seems to be composed of four subunits of the same size.Optimum pH and temperature for activity were found to be pH 8.5, and45℃, respectively. PAL showed certain thermostability and certainstability in the range pH 8.0～pH 9.8. Apparent Km value for L-phenylalanine was 2.6×10^(-5)M(pH 8.8, 40℃).
出处
《兰州大学学报（自然科学版）》
CAS
CSCD
北大核心
1991年第2期134-139,共6页
Journal of Lanzhou University(Natural Sciences)
关键词
无壳葫芦
PAL
提纯
植物
酶
cucurbita pepo linn
L-phenylalanine ammonia-Lyase
affinity chromatography
