Regulation of Rubber Biosynthetic Rate and Molecular Weight in Hevea brasiliensis by Metal Cofactor
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- 作者：Bernardo M. T. da Costa ; Jay D. Keasling ; and Katrina Cornish
- 刊名：Biomacromolecules
- 出版年：2005
- 出版时间：January 2005
- 年：2005
- 卷：6
- 期：1
- 页码：279 - 289
- 全文大小：782K
- 年卷期：v.6,no.1(January 2005)
- ISSN：1526-4602
文摘
Metal ion cofactors are necessary for prenyltransferase enzymes. Magnesium and manganese can be usedas metal ion cofactor by rubber transferase (a cis-prenyltransferase) associated with purified rubber particles.The rubber initiation rate, biosynthetic rate, and molecular weight produced in vitro from Hevea brasiliensisrubber transferase is regulated by metal ion concentration. In addition, 
varies significantly with[Mg2+]. 
decreases from 8000 ± 600 
M at [Mg2+] = 4 mM to 68 ± 10 M at [Mg2+] = 8 mM andincreases back to 970 ± 70 M at [Mg2+] = 30 mM. The highest affinity of rubber transferase for IPP·Mgoccurred when [Mg2+] = Amax (metal concentration that gives highest IPP incorporation rate). A metal ionis required for rubber biosynthesis, but an excess of metal ions interacts with the rubber transferase inhibitingits activity. The results suggest that H. brasiliensis could use [Mg2+] as a regulatory mechanism for rubberbiosynthesis and molecular weight in vivo.
varies significantly with[Mg2+]. decreases from 8000 ± 600 M at [Mg2+] = 4 mM to 68 ± 10 M at [Mg2+] = 8 mM andincreases back to 970 ± 70 M at [Mg2+] = 30 mM. The highest affinity of rubber transferase for IPP·Mgoccurred when [Mg2+] = Amax (metal concentration that gives highest IPP incorporation rate). A metal ionis required for rubber biosynthesis, but an excess of metal ions interacts with the rubber transferase inhibitingits activity. The results suggest that H. brasiliensis could use [Mg2+] as a regulatory mechanism for rubberbiosynthesis and molecular weight in vivo.