小麦胆色素原脱氨酶的电泳性质分析

The Characteristic Assay by Electrophoresis of Porphobilinogen Deaminase from Wheat

经反应红１２０亲和层析纯化的小麦胆色素原脱氨酶（Ｐｏｒｐｈｏｂｉｌｉｎｏｇｅｎｄｅａｍｉ－ｎａｓｅ，ＰＢＧＤ，ＥＣ．４，３，１，８），在ＳＤＳ—ＰＡＧＥ和ＩＥＦ—ＰＡＧＥ上均显示一条带，表明已ＰＢＧＤ纯化至均一，它的亚基分子量３６ＫＤ，ｐＩ为４．８。酶活性染色呈一条带，表明无同工酶存在。ＰＡＧＥ显示两条带，证明小麦幼苗中存在酶与底物结合的中间物。脲梯度电泳呈现之字形，在４ｍｏｌ／Ｌ的脲浓度下可使酶与底物结合的中间物解离。

The result of SDS-PAGE and IEF-PAGE analysis confirmed that the extract of porphobilinogen deaminase (PBGD,EC.4.3.1.8.) was homogeneous after purified by Reactive Red 120 affinity chramotography.This deaminase had a subunit of Mr 36 KD with pI 4 8.Nondenaturing PAGE showed two bands,indicating that PBGD can bind PBG to form intermediate complexes,which can be disrupted by urea of 4 mol/L.There appeared only one band in ewzymatic activity,indicating that this enzyme has no isozyme.