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Nearly 100 years ago Michaelis and Menten published their now classic paper [Michaelis, L., and Menten, M. L. (1913) Die Kinetik der Invertinwirkung. Biochem. Z. 49, 333-369] in which they showed that the rate of an enzyme-catalyzed reaction is proportional to the concentration of the enzyme-substrate complex predicted by the Michaelis-Menten equation. Because the original text was written in German yet is often quoted by English-speaking authors, we undertook a complete translation of the 1913 publication, which we provide as Supporting Information. Here we introduce the translation, describe the historical context of the work, and show a new analysis of the original data. In doing so, we uncovered several surprises that reveal an interesting glimpse into the early history of enzymology. In particular, our reanalysis of Michaelis and Menten's data using modern computational methods revealed an unanticipated rigor and precision in the original publication and uncovered a sophisticated, comprehensive analysis that has been overlooked in the century since their work was published. Michaelis and Menten not only analyzed initial velocity measurements but also fit their full time course data to the integrated form of the rate equations, including product inhibition, and derived a single global constant to represent all of their data. That constant was not the Michaelis constant, but rather Vmax/Km, the specificity constant times the enzyme concentration (kcat/Km × E0). [ABSTRACT FROM AUTHOR]

This paper explores the role of the business community in promoting sustainable consumption. While businesses play an important role in shaping social trends, including the growth of material consumption, allegations that individual corporations wield excessive power may have been overstated. Most of the time corporations are simply playing by the rules and culture of the market.Businesses have mostly assumed that their contribution to sustainability lies in improving eco-efficiency—staying within the current business framework. But sustainable consumption will require wider change, including shifts in the incentives that shape the actions of businesses and others, and a change in the culture that underlies market expectations. Firms, governments, the media and civil society may need to enter a dialogue together to develop a new story about the nature of prosperity and the role of the business community in promoting it. The initiative is most likely to come from civil society. [Copyright &y& Elsevier]

The Oxford Commission on Sustainable Consumption aims to promote debate and action to achieve sustainable consumption. It has met four times since it was established in 1999. Commission members have undertaken a number of projects around the world, working with communities to explore pathways to more sustainable consumption. This paper summarises the Commission’s progress and the messages emerging from its work. Current consumption trends are supported by a number of social trends, including individualisation, the spread of the market ethos, urbanisation, globalisation, and the increasing awareness of risk and uncertainty. However, these trends contain the seeds of their own limitation. In particular, increasing discourse about ethics and social goals may be the key to a shift towards more sustainable consumption. [Copyright &y& Elsevier]

A letter to the editor is presented in response to the article about the combination of fludarabine, melphalan and alemtuzumab, which was published online on May 14, 2007.

Lignocellulosic biomass is a potential source of renewable, low-carbon-footprint liquid fuels. Biomass recalcitrance and enzyme cost are key challenges associated with the large-scale production of cellulosic fuel Kinetic modeling of enzymatic cellulose digestion has been complicated by the heterogeneous nature of the substrate and by the feet that a true steady state caimot be attained. We present a two-parameter kinetic model based on the Michaelis-Menten scheme (Michaelis, L., and Menten, M. L. (1913) Biochem. Z., 49, 333-369) with a time-dependent activity coefficient analogous to fractal-like kinetics formulated by Kopehnan (Kopelman, R. (1988) Science 241, 1620-1626). We provide a mathematical derivation and experimental support to show that one of the parameters is a total activity coefficient and the other is an intrinsic constant that reflects the ability of the cellulases to overcome substrate recalcitrance. The model is applicable to individual cellulases and their mixtures at low-to-medium enzyme loads. Using biomass degrading enzymes from ceDulolytic bacterium Thermobijida fitsca, we show that the model can be used for mechanistic studies of enzymatic cellulose digestion. We also demonstrate that it applies to the crude supernatant of the widely studied cellulolytic fungus Tridioderma reesd; thus it can be used to compare cellulases from different organisms. The two parameters may serve a similar role to Vmax, KM, and Kcat in classical kinetics. A similar approach may be applicable to other enzymes with heterogeneous substrates and where a steady state is not achievable. [ABSTRACT FROM AUTHOR]

Objective To investigate risk factors associated with the acquisition of antibodies against Plasmodium vivax Duffy binding protein (PvDBP) - a leading malaria vaccine candidate - in a well-consolidated agricultural settlement of the Brazilian Amazon Region and to determine the sequence diversity of the PvDBP ligand domain (DBPII) within the local malaria parasite population. Methods Demographic, epidemiological and clinical data were collected from 541 volunteers using a structured questionnaire. Malaria parasites were detected by conventional microscopy and PCR, and blood collection was used for antibody assays and molecular characterisation of DBPII. Results The frequency of malaria infection was 7% (6% for P. vivax and 1% for P. falciparum), with malaria cases clustered near mosquito breeding sites. Nearly 50% of settlers had anti-PvDBP IgG antibodies, as detected by enzyme-linked immunosorbent assay (ELISA) with subject's age being the only strong predictor of seropositivity to PvDBP. Unexpectedly, low levels of DBPII diversity were found within the local malaria parasites, suggesting the existence of low gene flow between P. vivax populations, probably due to the relative isolation of the studied settlement. Conclusion The recognition of PvDBP by a significant proportion of the community, associated with low levels of DBPII diversity among local P. vivax, reinforces the variety of malaria transmission patterns in communities from frontier settlements. Such studies should provide baseline information for antimalarial vaccines now in development. [ABSTRACT FROM AUTHOR]