SPECIES VARIATION IN KINETIC-PROPERTIES OF RIBULOSE 1,5-BISPHOSPHATE CARBOXYLASE OXYGENASE
SPECIES VARIATION IN KINETIC-PROPERTIES OF RIBULOSE 1,5-BISPHOSPHATE CARBOXYLASE OXYGENASE
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DOI：
10.1016/0003-9861(83)90472-1
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发表时间：
1983-01-01
影响因子：
3.9
通讯作者：
OGREN, WL
中科院分区：
文献类型：
--
作者：
JORDAN, DB;OGREN, WL
测定并比较了不同物种核酮糖-1，5-二磷酸（RuBP）羧化酶/加氧酶的动力学参数。CO2/O2特异性（VcKo/VoKc）为约。80在来自几种C3物种[向日葵、番茄、紫花苜蓿、卷柏]和2种C4物种[稗草、马齿苋]的酶中。特异性值分别为58和70，被发现在酶从C4植物谷子和高粱双色。来自蓝细菌[Aphanocapsa alpicola，plectonema boryanum]的两种酶具有约50.用Mn 2+取代Mg 2+使CO2/O2特异性降低约1/3。20的所有酶，除了红杜鹃，这是减少了10倍。在102 μ M CO2下测量的KMg 2+（表观）值在不同RuBP羧化酶/加氧酶之间变化8倍[菠菜、烟草、大豆、苋、玉米、水华束丝藻、R. rubrum]。具有高KMg 2+（表观）值的酶通常对CO2具有高Km。在所有酶中，RuBP抑制CO2/Mg 2+活化的速率，尽管抑制来自蓝细菌A的酶中的活化所需的RuBP浓度。flos-aquae与其它高等植物结构型酶相比提高了一个数量级。从不同物种中分离的RuBP羧化酶/加氧酶的动力学特性中发现的广泛变化似乎部分由过去的进化压力和酶功能所在的当前物理化学环境决定。
Several kinetic parameters of ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase from different species were measured and compared. The CO2/O2 specificity (VcKo/VoKc) was .apprx. 80 in the enzymes from several C3 species [Helianthur maximus, Lycopersicon esculentum, Medicago sativa, Petroselinum crispum] and 2 C4 species [Echinochloa crus-galli, Portulaca oleracea]. Specificity values of 58 and 70, respectively, were found in enzymes from the C4 plants Setaria italica and Sorghum bicolor. Two enzymes from cyanobacteria [Aphanocapsa alpicola, plectonema boryanum] had values of .apprx. 50. Substitution of Mn2+ for Mg2+ reduced the CO2/O2 specificity by a factor of .apprx. 20 for all enzymes except that of Rhodospirillum rubrum, which was reduced by a factor of 10. Values for KMg2+(apparent) measured at 102 .mu.M CO2 were varied by a factor of 8 between different RuBP carboxylase/oxygenase enzymes [Spinacia oleracea, Nicotiana tabacum, Glycine max, Amaranthus hybridus, Zea mays, Aphanizomenon flos-aque, R. rubrum]. Enzymes with high KMg2+(apparent) values generally had high Km for CO2. The rate of CO2/Mg2+ activation was inhibited by RuBP in all enzymes, although the concentration of RuBP required to inhibit activation in the enzyme from the cyanobacterium A. flos-aquae was increased by an order of magnitude compared ot other higher plant structural-type enzymes. The wide variation found in the kinetic properties of RuBP carboxylase/oxygenase isolated from diverse species appears to be determined in part by past evolutionary pressures and the present physicochemical environment in which the enzyme functions.