Cold-active enzymes and their applications in industrial fields - A review
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- Cold Active Enzymes, Metagenomics, Psychrophile, Microbial Enzymes
- Al-Maqtari, Qais Ali; AL-Ansi, Waleed; Mahdi, Amer Ali
- Cold-active enzymes are produced by organisms adapted to permanently cold habitats. Due to the depressive effect of low temperatures on reaction rates, these enzymes have to be adapted to secure appropriate reaction rates in those organisms that often thrive in environments characterized by temperatures close or below the freezing point of water. They are encountered in all prokaryotic or eukaryotic organisms adapted to cold such as microorganisms, invertebrates, insects and ﬁsh originating from the Arctic and Antarctic zones, as well as from alpine regions, glaciers or permafrost zones. They are characterized by a high speciﬁc activity at low temperatures, in any case higher than that of their mesophilic and thermophilic counterparts. This higher speciﬁc activity is generally accompanied by a decrease in thermal stability illustrated by a shift of the apparent optimum towards low temperatures, and by an important decrease in the thermodynamic stability characterized by a signiﬁcantly lower stabilization enthalpy. The generally low stability induces an increase in the ﬂexibility of the overall ediﬁce or of crucial zones for activity of the molecular structure. There is apparently a continuum in the adaptation since some enzymes display extreme adaptation illustrated by a severe shift of the activity towards low temperatures whereas others are moderately adapted. This probably depends on their position in a metabolic pathway, on their intracellular or extracellular localization, on the environmental temperature and on the evolutionary history of the organisms.
Full text: IJRAS_775_FINAL.pdf