ARTIFICIAL INTERMEDIATES IN REACTION OF HAEMOGLOBIN - FUNCTIONAL AND CONFORMATIONAL PROPERTIES OF CYANMET INTERMEDIATES
ARTIFICIAL INTERMEDIATES IN REACTION OF HAEMOGLOBIN - FUNCTIONAL AND CONFORMATIONAL PROPERTIES OF CYANMET INTERMEDIATES
复制标题
DOI：
10.1016/0022-2836(70)90257-3
复制
发表时间：
1970-01-01
影响因子：
5.6
通讯作者：
WINTERHA.KH
中科院分区：
文献类型：
--
作者：
BRUNORI, M;AMICONI, G;WINTERHA.KH
血红蛋白的人工氰胺中间体是通过将氰胺链与其氧合的伙伴混合得到的。在pH 7和20℃时，两种中间体的氧亲和力相似，介于血红蛋白和分离链之间；对于（α+β+ CN）， Hill方程中的N值等于1，但对于（α+ N+ β）， Hill方程中的N值可能略高（~1.1 ~ 1.2）。两种中间体的碱性玻尔效应非常相似，但在（α+β+ CN）中缺乏酸性玻尔效应。在与一氧化碳的反应中，中间产物比血红蛋白快一些，但比分离链慢得多。配体与血红蛋白结合时的构象变化是由β93巯基的反应性变化和233 nm旋转强度的变化所暗示的。在（α+ CN+β）中加入氧后，反应性巯基与对汞苯甲酸盐结合的时间过程发生了变化，而其他中间体的氧化不改变汞苯甲酸盐的结合速率。由于氧结合，在233 nm处[R ']的值发生了变化，这在两种情况下都是相同的（Δ[R ']233 ~ - 3%）。
Artificial cyanmet intermediates of haemoglobin were obtained by mixing cyanmet chains with their oxygenated partners. At pH 7 and 20 °C, the oxygen affinity of the two intermediates is similar and lies between that of haemoglobin and the isolated chains; the value ofnin the Hill equation is equal to 1 for (α+β+ CN) but may be slightly higher (~1.1 to 1.2) for (α+ N+ β). The alkaline Bohr effect is very similar for the two intermediates, but the acid Bohr effect is lacking in (α+β+ CN). In the reaction with carbon monoxide, the intermediates are somewhat faster than haemoglobin but very much slower than the isolated chains. Conformational changes upon ligand binding to haemoglobin are implied by changes in reactivity of theβ93sulphydryl groups and by changes in the rotational strength at 233 nm. Addition of oxygen to (α+ CN+β) is followed by a change in the time-course ofp-mercuribenzoate binding by the reactive sulphydryl groups, whereas oxygenation of the other intermediate does not modify the rate of mercuribenzoate binding. A change in the value of [R′] at 233 nm as a result of oxygen binding is observed, which is about the same in both cases (Δ[R′]233∼- 3%).