Lequeux Gaspard, Johansson Louise, Maertens Jo, Vanrolleghem Peter A, Lidén Gunnar
BIOMATH, Department of Applied Mathematics, Biometrics and Process Control, Ghent University, Coupure Links 653, Belgium.
Biotechnol Prog. 2006 Jul-Aug;22(4):1056-70. doi: 10.1021/bp060014u.
The present contribution focuses on the mathematical techniques used to solve steady state metabolic models for the case of an overdetermined system. Even when parts of the system are underdetermined it is possible to solve the model partially and obtain statistically meaningful results. This is illustrated with data gathered from a set of E. coli W3110.shik1 phosphate- or carbon-limited continuous cultures. It is shown that the low yield in shikimate for C-limited cultures is not due to a lower flux going to the shikimate pathway but is caused by a high secretion of byproducts. Carbon-limited cultures could be better for shikimate production than carbon-abundant cultures provided the byproduct secretion is reduced. Finally, flux calculations are compared with RNA expression data.
本论文着重探讨用于求解超定系统稳态代谢模型的数学技术。即使系统的某些部分是欠定的，也有可能部分求解该模型并获得具有统计学意义的结果。这一点通过从一组大肠杆菌W3110.shik1磷酸盐或碳限制连续培养实验收集的数据得到了说明。结果表明，碳限制培养条件下莽草酸产量低并非由于进入莽草酸途径的通量较低，而是由副产物的高分泌所致。如果能够减少副产物分泌，那么碳限制培养条件可能比碳充足培养条件更有利于莽草酸的生产。最后，对通量计算结果与RNA表达数据进行了比较。
