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Human glyoxalase I. Twa zinc ions that are needit for the enzyme tae catalyze its reaction are shawn as purpie spheres, an an enzyme inhibitor cried S-hexylglutathione is shawn as a space-fillin model, fillin the twa active steids.

Enzymes are macromolecular biological catalysts. Enzymes accelerate chemical reactions. The molecules upon that enzymes mey act are cried substrates an the enzyme converts the substrates intae different molecules kent as products. Awmaist aw metabolic processes in the cell need enzyme catalysis in order tae occur at rates fast eneuch tae susteen life.[1]:8.1 Metabolic pathweys depend upon enzymes tae catalyze individual steps. The study o enzymes is cried enzymology an a new field o pseudoenzyme analysis haes recently growed up, recognisin that in evolution, some enzymes hae lost the abeelity to cairy oot biological catalysis, that is eften reflectit in thair amino acid sequences an unusual 'pseudocatalytic' properties.[2][3]

Enzymes are kent tae catalyze mair nor 5,000 biochemical reaction teeps.[4] Maist enzymes are proteins, awtho a few are catalytic RNA molecules. The latter are cried ribozymes. Enzymes' specificity comes frae thair unique three-dimensional structurs.

Lik aw catalysts, enzymes increase the reaction rate bi lawerin its activation energy. Some enzymes can mak thair conversion o substrate tae product occur mony millions o times fester. An extreme ensaumple is orotidine 5'-phosphate decarboxylase, that allous a reaction that wad ithergates tak millions o years tae occur in milliseiconts.[5][6] Chemically, enzymes are lik ony catalyst an are nae consumed in chemical reactions, nor do thay alter the equilibrium o a reaction. Enzymes differ frae maist ither catalysts bi bein muckle mair speceefic. Enzyme activity can be affectit bi ither molecules: inhibitors are molecules that decrease enzyme activity, an activators are molecules that increase activity. Mony therapeutic drogs an pushions are enzyme inhibitors. An enzyme's activity decreases merkedly outside its optimal temperatur an pH.

Some enzymes are uised commercially, for example, in the synthesis o antibiotics. Some hoosehaud products uise enzymes tae speed up chemical reactions: enzymes in biological washin pouders brak doun protein, stairch or fat stains on claes, an enzymes in meat tenderiser brak doun proteins intae smawer molecules, makkin the meat easier tae chew.

References[eedit | eedit soorce]

  1. Stryer L, Berg JM, Tymoczko JL (2002). Biochemistry (5th ed.). San Francisco: W.H. Freeman. ISBN 0-7167-4955-6.Open Access logo PLoS transparent.svg
  2. Murphy JM, Farhan H and Eyers PA (2017) Bio-Zombie: the rise of pseudoenzymes in biology.Biochem Soc Trans. 45:537–544
  3. Murphy JM, et al. (2014). "A robust methodology to subclassify pseudokinases based on their nucleotide-binding properties". Biochemical Journal. 457 (2): 323–334. doi:10.1042/BJ20131174. PMID 24107129.
  4. Schomburg I, Chang A, Placzek S, Söhngen C, Rother M, Lang M, Munaretto C, Ulas S, Stelzer M, Grote A, Scheer M, Schomburg D (January 2013). "BRENDA in 2013: integrated reactions, kinetic data, enzyme function data, improved disease classification: new options and contents in BRENDA". Nucleic Acids Research. 41 (Database issue): D764–72. doi:10.1093/nar/gks1049. PMC 3531171. PMID 23203881.
  5. Radzicka A, Wolfenden R (January 1995). "A proficient enzyme". Science. 267 (5194): 90–931. Bibcode:1995Sci...267...90R. doi:10.1126/science.7809611. PMID 7809611.
  6. Callahan BP, Miller BG (December 2007). "OMP decarboxylase—An enigma persists". Bioorganic Chemistry. 35 (6): 465–9. doi:10.1016/j.bioorg.2007.07.004. PMID 17889251.