摘要
本文用紫外光谱研究了等离子点附近HSA或BSA (?)Cu(Ⅱ)或Ni(Ⅱ)金属中心的结构。结果表明:在pH4.0～5.3时,Cu(Ⅱ)—HSA配合物在低浓度时独具五配位的四方锥构型,高浓度时(>10^(-4)mol·1^(-1))为四配位的四方平面构型,Cu(Ⅱ)—BSA、Ni(Ⅱ)—BSA在上述pH范围内均只存在四方平面构型。Cu(Ⅱ)、Ni(Ⅱ)结合位置与生理pH下的相同,均在白蛋白的N端三肽段上,与Asp^1的α-NH_2、His^3的咪唑基N及两个去质子肽氮配位,Cu(Ⅱ)在HSA中的第五结合基团为Asp^1的羧基。本文还对上述pH效应进行了讨论。
In this paper, the structure of the Cu(II) or Ni(II) metal center in HSA or BSA nearby the isoionic point have been studied by ultraviolet spectroscopy. The results show in pH 4.0-5.3 range, the configuration of Cu(II )-HSA complexes is uniquely the pcntacoordinated square-pyramidal at concentrations lower than 4.0 × 10-4mol·l-1. But at concentrations greater than 4.0 × 10-4mol·l-1, it takes the tctracoordinated square-plannar form. In above pH range, the configuration of Cu(II )-BSA, Ni(II )-BSA are only the tetracoordinated square-plannar. The binding sites of Cu(II), Ni(II) are same as those at physiological pH, they are all located at the N-terminal sequence of HSA or BSA, and coordinated with -NH2, imidazoyl and two pcptide nitrogens. In Cu(II )-HSA, the fifth binding group is COO- of Asp1. Above pH effect has also been discussed.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
1992年第4期382-386,共5页
Chinese Journal of Inorganic Chemistry
关键词
镍
铜
血清白蛋白
构型
络合物
Cu( II)-scrum albumin Ni(II)-serum albumin configuration optical electronegativity pH effect
