Journal
BIOCHEMISTRY
Volume 55, Issue 12, Pages 1681-1688Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acs.biochem.5b01094
Keywords
-
Categories
Funding
- University of Waikato Ph.D.
- Marsden Fund of New Zealand [08-UOW-57]
- BBSRC [BB/L01386X/1, BB/L018756/1]
- EPSRC [EP/M022609/1]
- BBSRC David Phillips Fellowship
- Core Funding to New Zealand Crown Research Institutes
- Graduate Women Education Trust scholarships
- Biotechnology and Biological Sciences Research Council [BB/L018756/1, BB/L01386X/1, BB/M026280/1] Funding Source: researchfish
- Engineering and Physical Sciences Research Council [EP/M022609/1] Funding Source: researchfish
- BBSRC [BB/M026280/1, BB/L018756/1, BB/L01386X/1] Funding Source: UKRI
- EPSRC [EP/M022609/1] Funding Source: UKRI
Ask authors/readers for more resources
One of the critical variables that determine the rate of any reaction is temperature. For biological systems, the effects of temperature are convoluted with myriad (and often opposing) contributions from enzyme catalysis, protein stability, and temperature-dependent regulation, for example. We have coined the phrase macromolecular rate theory (MMRT) to describe the temperature dependence of enzyme-catalyzed rates independent of stability or regulatory processes. Central to MMRT is the observation that enzyme-catalyzed reactions occur with significant values of Delta C-p that are in general negative. That is, the heat capacity (C-p) for the enzyme-substrate complex is generally larger than the Cp for the enzyme-transition state complex. Consistent with a classical description of enzyme catalysis, a negative value for Delta C-p is the result of the enzyme binding relatively weakly to the substrate and very tightly to the transition state. This observation of negative Delta C-p has important implications for the temperature dependence of enzyme-catalyzed rates. Here, we lay out the fundamentals of MMRT. We present a number of hypotheses that arise directly from MMRT including a theoretical justification for the large size of enzymes and the basis for their optimum temperatures. We rationalize the behavior of psychrophilic enzymes and describe a psychrophilic trap which places limits on the evolution of enzymes in low temperature environments. One of the defining characteristics of biology is catalysis of chemical reactions by enzymes, and enzymes drive much of metabolism. Therefore, we also expect to see characteristics of MMRT at the level of cells, whole organisms, and even ecosystems.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available