title: Testing Macromolecular Rate Theory

authors: Kraakman, Kirsty Leigh

subjects: enzymes

abstract: Enzymatic rate increase with respect to temperature has widely been described by transition-state theory. The experimentally observed rate decline above an optimum temperature (Tₒₚₜ) for enzymes has previously been attributed to thermal denaturation, despite the known discrepancies with this rationalisation. Recently, a new model has been proposed to describe the temperature dependence of enzymatic rates: macromolecular rate theory (MMRT). This new theory incorporates heat capacity into the rate equation to provide a more robust thermodynamic description of rates, and account for the distinct curvature seen in biological temperature-rate profiles. The current study explores the effect of enzyme vibrational modes on heat capacity, and how alterations to the distribution of these modes, by heavy isotope substitution, affect the change in heat capacity along the reaction coordinate. The results presented show clear evidence for the role of vibrational mode frequency distributions in governing the curvature of temperature-rate profiles, and present a hypothesis for how this shift differs for the enzyme-substrate complex and the enzyme-transition state complex. The study also addresses the ability of MMRT to accurately model enzymatic rates over a wide temperature range for two different enzymes. As a result of this study, a new MMRT equation was generated to include a temperature dependence term for the heat capacity, a factor previously considered negligible. The data generated has shown that heat capacity is temperature dependent and this is a significant factor in accurately describing enzymatic rates with respect to temperature. In particular, for complex enzymatic reactions whose enthalpy distribution is significantly narrowed over the reaction co-ordinate. These findings have helped to develop MMRT to provide more accurate descriptions of a broader range of data. Additionally, the conclusions regarding vibrational mode distribution provide insight into the physical basis for heat capacity changes over the course of the enzymatic reaction. Investigation of the hypotheses generated from this research will offer further insight into the mechanistic contributions of vibrational modes and heat capacity in enzyme catalysis.

text: Testing Macromolecular Rate Theory Enzymatic rate increase with respect to temperature has widely been described by transition-state theory. The experimentally observed rate decline above an optimum temperature (Tₒₚₜ) for enzymes has previously been attributed to thermal denaturation, despite the known discrepancies with this rationalisation. Recently, a new model has been proposed to describe the temperature dependence of enzymatic rates: macromolecular rate theory (MMRT). This new theory incorporates heat capacity into the rate equation to provide a more robust thermodynamic description of rates, and account for the distinct curvature seen in biological temperature-rate profiles. The current study explores the effect of enzyme vibrational modes on heat capacity, and how alterations to the distribution of these modes, by heavy isotope substitution, affect the change in heat capacity along the reaction coordinate. The results presented show clear evidence for the role of vibrational mode frequency distributions in governing the curvature of temperature-rate profiles, and present a hypothesis for how this shift differs for the enzyme-substrate complex and the enzyme-transition state complex. The study also addresses the ability of MMRT to accurately model enzymatic rates over a wide temperature range for two different enzymes. As a result of this study, a new MMRT equation was generated to include a temperature dependence term for the heat capacity, a factor previously considered negligible. The data generated has shown that heat capacity is temperature dependent and this is a significant factor in accurately describing enzymatic rates with respect to temperature. In particular, for complex enzymatic reactions whose enthalpy distribution is significantly narrowed over the reaction co-ordinate. These findings have helped to develop MMRT to provide more accurate descriptions of a broader range of data. Additionally, the conclusions regarding vibrational mode distribution provide insight into the physical basis for heat capacity changes over the course of the enzymatic reaction. Investigation of the hypotheses generated from this research will offer further insight into the mechanistic contributions of vibrational modes and heat capacity in enzyme catalysis.

year: 2017

title: Covenons! We owe our store to the company’s soul...

authors: Yoos ii, Charles J.

subjects: business organization

abstract: We argue that in contemporary business organizations, in which fundamental purpose is construed to be increased value—especially in ‘participative’ organizations, in which non–hierarchal interaction (for example, work teams) is the norm; and in ‘adaptive’ organizations, in which unpredictable change is the rule—a process of values covenanting will be much more valueable than just espoused values or even values covenants. We propose such a process model for organizational values covenanting and argue that such covenanting reflects an anthropomorphism of the human character development process, validated in terms of the theory of viable systems.

text: Covenons! We owe our store to the company’s soul... We argue that in contemporary business organizations, in which fundamental purpose is construed to be increased value—especially in ‘participative’ organizations, in which non–hierarchal interaction (for example, work teams) is the norm; and in ‘adaptive’ organizations, in which unpredictable change is the rule—a process of values covenanting will be much more valueable than just espoused values or even values covenants. We propose such a process model for organizational values covenanting and argue that such covenanting reflects an anthropomorphism of the human character development process, validated in terms of the theory of viable systems.

year: 2008

title: Research support in New Zealand University Libraries

authors: Howie, Jess

abstract: Researcher-facing librarians in New Zealand are providing guidance across more of the research lifecycle than ever before in response to an increasingly complex scholarly ecosystem. This research explored the development of research support through survey responses from all eight New Zealand University Libraries. From the responses it was possible to ascertain the level of services offered or planned in the four key areas of research impact, Research Data Management, scholarly communication and Kaupapa Māori research. Skills gaps and barriers to service development were also identified. Comparison with an earlier study revealed that research impact and Research Data Management services have developed well over the last 6 years. A good level of maturity was identified in scholarly communication services but support for Kaupapa Māori research was identified as an area for development. Barriers to service development included lack of resourcing and low recognition of library value from the wider institution.

text: Research support in New Zealand University Libraries Researcher-facing librarians in New Zealand are providing guidance across more of the research lifecycle than ever before in response to an increasingly complex scholarly ecosystem. This research explored the development of research support through survey responses from all eight New Zealand University Libraries. From the responses it was possible to ascertain the level of services offered or planned in the four key areas of research impact, Research Data Management, scholarly communication and Kaupapa Māori research. Skills gaps and barriers to service development were also identified. Comparison with an earlier study revealed that research impact and Research Data Management services have developed well over the last 6 years. A good level of maturity was identified in scholarly communication services but support for Kaupapa Māori research was identified as an area for development. Barriers to service development included lack of resourcing and low recognition of library value from the wider institution.

year: 2019-01-01