title: The universality of enzymatic rate-temperature dependency.
abstract: Organismal adaptation to extreme temperatures yields enzymes with distinct configurational stabilities, including thermophilic and psychrophilic enzymes, which are adapted to high and low temperatures, respectively. These enzymes are widely assumed to also have unique rate-temperature dependencies. Thermophilic enzymes, for example, are considered optimal at high temperatures and effectively inactive at low temperatures due to excess rigidity. Surveying published data, we find that thermophilic, mesophilic, and psychrophilic enzymes exhibit indistinguishable rate-temperature dependencies. Furthermore, given the nonenzymatic rate-temperature dependency, all enzymes, regardless of their operation temperatures, become >10-fold less powerful catalysts per 25 °C temperature increase. Among other factors, this loss of rate acceleration may be ascribed to thermally induced vibrations compromising the active-site catalytic configuration, suggesting that many enzymes are in fact insufficiently rigid.
authors: Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel. Electronic address: mikael.elias@weizmann.ac.il.
authors: Mikael
authors: M
authors: Elias
authors: Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
authors: Grzegorz
authors: G
authors: Wieczorek
authors: Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
authors: Shaked
authors: S
authors: Rosenne
authors: Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel. Electronic address: tawfik@weizmann.ac.il.
authors: Dan S
authors: DS
authors: Tawfik
mesh_terms: D000220:Adaptation, Biological; D019843:Archaeal Proteins / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry; D055162:Biocatalysis; D020134:Catalytic Domain; D004795:Enzyme Stability; D004798:Enzymes / Q000737:chemistry* / Q000235:genetics; D019143:Evolution, Molecular; D007700:Kinetics; D013696:Temperature
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D004798:Enzymes
keywords: active-site preorganization; enzyme dynamics; rate temperature–dependency; thermal vibrations; thermophilic enzymes