3. 3 Life depends on series of chemical reactions Chemical reactions are far slow to maintain life Living system has designed catalysts to fasten the specific reactions

4. Enzymes accelerate the rate of chemical reactions in living organisms. Like all catalysts, enzymes work by lowering the amount of activation energy needed for a reaction to occur and thus dramatically accelerating the rate of the reaction. Enzymes are proteins produced by different cells of humans, animals, plants and microorganisms

5. آنزیم ها سرعت واکنش های بیوشیمیایی را افزایش می دهند اما تاثیری بر وضعیت تعادلی واکنش ندارند.

6. Enzymes – Definition A reusable protein molecule that brings about chemical change while remaining unchanged itself.

7. Enzymes – Break and form covalent bonds – Move large structures – Effect three dimensional structure – Regulate gene expression

8. Enzymes lower an energy of activation (E A ) reduce the time to reach the reaction equilibrium don´t change the equilibrium position of the reaction are not consumed or changed by the reaction are specific can be regulated self study

9. Cells & Enzymes Enzymes Made of protein Present in all living cells Converts substrates into products Biological catalysts Increase the rate of chemical reactions Remain unchanged by chemical reaction

10. آنزیم ها در مقایسه با کاتالیزور ها بسیار اختصاصی عمل می کنند: اختصاصی بودن آنزیم ها به 2 صورت است :  Absolute Specific ( اختصاصی مطلق) مثال: گلوگوکیناز که فقط بر روی گلوکزاثر دارد  Broad Specificity ( اختصاصی گسترده) مثال : آنزیم ترپسین که بر روی پیوند های پپتیدی که اسید های آمینه Arg, Lys وجود دارد عمل می کند

11. S P E بطور کلی در واکنش های بیوشیمیایی که توسط آنزیم کاتالیز می شود 3 جسم شرکت دارد ماده اولیه ( سوبسترا) – جسمی که تحت تاثیر آنزیم قرار می گیرد آنزیم – روی سوبسترا اثر نموده و واکنش را کاتالیز می کند محصول – در جریان واکنش تولید می شود S E P

14. A + B  C + D سرعت واکنش در حضور آنزیم 10 3 – 11 10 برابر سرعت واکنش بدون حضور آنزیم خواهد بود A + B C + D

15. Enzyme kinetics activity, units 1 IU = 1 μmole of a substrate transformed per 1 minute  1 katal = 1 mole of a substrate transformed per 1 sec 1 katal= 6 x 10 7 IU S P E

16. A-X + A B E A + B-X E E-X B B-X ملکول های آنزیم در واکنش دخالت می کنند اما مصرف نمی شوند بنابر این یک ملکول آنزیم می تواند میلیون ها ملکول سوبسترا را به محصول تبدیل نماید

17. One Enzyme – One Reaction There are thousands of different enzymes in your body. Each enzyme has its own unique protein structure and shape, which is designed to match or COMPLEMENT its substrate.

18. Active Site(مکان فعال آنزیم) مکان فعال آنزیم سوبسترای هر آنزیم تنها به مکان مخصوصی از آنزیم پیوند می گردد که مکان فعال آنزیم نامیده می شود مکان فعال حالت 3 بعدی دارد که برای هر انزیم اختصاصی است مکان فعال هر آنزیم مجموعه ای اسید های امینه است که در اثر تا خوردگی و روی هم قرار گرفتن زنجیره پلی پپتیدی شکل می گیرد مکان فعال آنزیم درون آنزیم فرو رفته است E Active Site S

19. Enzyme is a biocatalyst:biocatalyst

20. 1890 -Fischer فرضیه : سوبسترای یک آنزیم به جایگاه خاصی از آنزیم بنام جایگاه فعال Active Site متصل می شود شکل جایگاه مکمل سوبسترا می باشد محدوده جزئی – ساختمان 3 بعدی – شکل معین lock-and-key’ hypothesis EE

21. The lock and key hypothesis states that the active site specifically matches the shape of the substrate molecule enzyme Each enzyme is specific to one substrate molecule or type of molecule active site S

22. Lock & Key Hypothesis An enzyme only acts on one type of substrate. Therefore, the enzyme is said to be SPECIFIC to its one substrate. The shape of the active site (binding site) of the enzyme, matches the shape of the substrate. Allowing the two molecules to bind during the chemical reaction. This theory of enzyme action is called the ‘lock-and-key’ hypothesis.

23. جایگاه فعال آنزیم شکل معینی ندارد و در هنگام ترکیب با سوبسترا به شکل مطلوب و یا شکل مکمل سوبسترا در می آید این پدیده را تناسب القایی می نامند Induction Fit E E S S

26. The figure is found at: http://fig.cox.miami.edu/~cmallery/255/255enz/enzymology.htm (December 2006)http://fig.cox.miami.edu/~cmallery/255/255enz/enzymology.htm پیوند بین آنزیم و سوبسترا از نوع اتصالات سست و ضعیف می باشد ولی گاها می تواند از نوع اتصالات کووالانسی باشد ( ترپسین). E + S ESE + P الکترواستاتیکی هیدروژنی واندروالسی (هیدروفوب)

27. Structure of enzyme primary structure second & tertiary structureA precise 3-dimensional shape: linear array of a.a. (primary structure) folds and twists into a specific configuration (second & tertiary structure) simple (protein only) conjugatedMay be a simple enzyme (protein only) or conjugated enzyme Conjugated enzymes need other non-protein molecules for activation (protein + non-protein) ApoenzymeCofactorHoloenzyme Apoenzyme Cofactor Holoenzyme

28. Cofactors non-protein: Metal ions and organic cofactors (usually derived from B vitamins) are major groups of cofactors. فلزات Prosthetic groups)) معمولا با پیوند های قوی در ساختمان پروتئینی آنزیم ها شرکت می کنند : Metalloenzyme Coenzyme کوفاکتور هایی که بصورت ترکیبات آلی نظیر ویتامین ها هستند : Coenzyme

29. HoloenzymeHoloenzyme = Apoenzyme – Large molecular wt. – All protein – Contains active site + Coenzyme – Organic or Prostatic – Metallic Cofactor

31. 31

32. Enzymes Naming Classification

33. When enzymes were first discovered scientists named them. Although they added the “in” suffix to most there was no uniformly accepted method of naming enzymesTrypsinPepsinChymotrypsin نامگذاری تجربی

34. Today enzyme’s name is derived from its substrate or the chemical reaction it catalyzes, with the word ending in “-ase” ((نامگذاری براساس نوع سوبسترا یا نوع واکنش + آز a) Substrate name + -ase(Amylase) b) Reaction type + -ase (Dehydrogenase) Cellulase, protease, amylase, lipase, glucose oxidase, DNA polymerase Decarboxylase, Hydrolase, Dehydrogenase, Abbreviations of enzymes * used in medicine LDH, ALT, ALP,…

35. 35 type of reaction the enzyme catalyzes Now, each protein is given an Enzyme Classification Number (EC). The method of classification is by the type of reaction the enzyme catalyzes EC

36.  EC 1 – Oxidoreductases  EC 2 – Transferases  EC 3 – Hydrolases  EC 4 – Lyases  EC 5 – Isomerases  EC 6 – Ligases

37. Oxidoreductases 1) Oxidoreductases: A ox + B red  A red + B ox * dehydrogenase (H - or H) * reductase * oxidase * peroxidase (various peroxides) * oxygenase (O 2 ) * hydroxylase (= monoxygenase; -OH) واکنش های اکسیداسیون و احیا را کاتالیز می کنند 0 باعث اکسیداسیون یک ملکول و احیائ ملکول دیگر می شوند. این آنزیم ها اغلب دارای یک کوانزیم می باشند

38. Oxidoreductases

39. Alcohol Dehydrogenase: ADH CH 3 CH 2 OH + NAD + CH 3 CH 2 O + H + +NADH Catalyses conversion of ethanol to aldehyde using co-enzyme NAD+ NAD+ oxidized to NADH reduced

41. Transferases: 2) Transferases: A-x + B  A + B-x * grouptransferase (e.g. aminotransferase) * kinase (= phosphotransferase) * phosphorylase * Transketolase * Transaldolase انتقال گروهایی را از ملکولی به ملکول دیگر کاتالیز می کنند ( بجز هیدروژن)

42. CH3

43. G + ATP → G6p + ADP گلوکوکیناز:

44. Transferases

45. Hydrolases: 3) Hydrolases: A-B + H 2 O  A-H + B-OH * esterase (R 1 -CO-O-R 2 ) * phosphatase (phosphate-O-R)  P i !!! * phosphodiesterase (R 1 -O-phosphate-O-R 2 ) * nuclease, peptidase, glycosidase, lipase عمل هیدرولیز پیوند های مختلف را انجام می دهند

46. Hydrolases

47. 4) lyases:A-x  B + x * decarboxylase (  CO 2 ) * dehydratase (  H 2 O) * synthase برداشت گروههایی را کاتالیز می کنند که می تواند با تشکیل پیوند دوگانه همراه باشد ( یا برعکس) catalyze the cleavage of C-C, C-O, C-S and C-N bonds by means other than hydrolysis or oxidation. leaving double bonds or rings, or conversely adding groups to double bonds

48. Lyases

50. 5) isomerases:A  iso-A * epimerase (monosacharide  its epimer) * mutase (rearangement of a phosphate group) عمل ایزومری شدن را کاتالیز می کنند: سیس – ترانس

51. Isomerases واکنش های انتقال گروهها را در درون ملکول کاتالیز می نمایند ایزومراز – اپی مراز... تبدیل گلیسرآلدئید فسفات به دی هیدروکسی استن فسفات توسط آنزیم ایزومراز

53. 6) ligases:A + B + ATP  A-B + ADP + P i * synthetase * carboxylase این آنزیم ها باعث پیوند و ترکیب 2 ملکول می شوند. در حالی که انرژی ایجاد پیوند با شکسته شدن ATP تامین می گردد

54. Ligases CH3-CO-S-COA + CO2 → COOH-CH2-CO-S-COA ATP ADP + Pi تشکیل مالونیل کوانزیم آ از استیل کوانزیم آ توسط آنزیم لیگاز

55. Scheme of Enzyme Classification by Iec The IEC gives a code and each letter contains it’s own significance in relation to that particular enzyme. During classification every enzyme is prefixed by EC, followed by the digits. For example: oxidoreductases EC 1.1.1.1 (a)The first digit denotes “Class” of the enzyme (b)The second digit indicates “Sub-class” of the enzyme (c)The third digit gives “Sub sub-class” of the enzyme (d)The fourth digit in the code is “Serial number” of the enzyme

56. Kinetics Temperature Effect PH Effect Enzyme Concentration Effect Substrate Concentration Effect

57. At low temperatures enzyme controlled reactions go slowly because the molecules have low kinetic energy. The rate of an enzyme controlled reaction is affected by temperature اثر حرارت بر واکنش های آنزیمی

58. But this only occurs up to the optimum temperature (usually about 40 o C) The temperature at which the rate of reaction is fastest is known as the optimum temperature When temperature increases the reaction also increases as the molecules have more kinetic energy

59. After the optimum temperature the heat causes the enzyme to denature The enzyme changes shape and the active site no longer matches the shape of the substrate molecule

60. افزایش حرارت دارای 2 اثر مخالف در سرعت واکنش های آنزیمی است افزایش سرعت واکنش غیر فعال کردن آنزیم

61. Rate Of Reaction Temperature/ o C 010203040506070 Optimum temperature Enzyme is denaturing Rate of reaction of an enzyme reaction changes at different temperatures Molecules gain kinetic energy

62. 2.5 Effect of High Temperature Notes on DenaturationDenaturation Notes on Optimum temp What happens to the activity of an enzyme at high temperatures?

64. Enzymes prefer to work at an optimum pH. Outside of its pH range the enzyme is denatured. Rate Of Reaction pH 1 2 3 4 5 6 7 8 9 10 11 12 pepsinamylase The activity and shape of enzymes is also affected by pH Optimum pH

65. Effect of pH on enzymes When the pH changes outwith optimal conditions, the shape of the active site of the enzyme alters and the enzyme is denatured.

66. Movie Effect of pH on enzymes When the pH changes outwith optimal conditions, the shape of the active site of the enzyme alters and the enzyme is denatured.

67. تغییرات PH سبب تغییر و غیر فعال شدن پروتئین آنزیم می گردد سبب تغییر در یونیزاسیون سوبسترا و شکل فضایی آن می گردد سبب تغییر در یونیزاسیون اسید های آمینه موجود در جایگاه فعال شده و بر میل ترکیبی آنزیم و سوبسترا موثر است

68. Effect of pH on enzyme activity Most enzymes work best at a pH close to neutral (pH 5-7), but there are some exceptions. Pepsin, an enzyme found in the stomach, has an optimum pH of 2. PH ای که در آن آنزیم حداکثر فعالیت را از خود نشان می دهد PH اپتیموم:

70. Substrate Saturation of an Enzyme A. Low [S] B. 50% [S] or K m C. High, saturating [S]

73. The activity is related to a constant concentration of an enzyme: [E] = constant

74. Effect of substrate

75. Michaelis-Menten Equation V 0 = V max [S] K m +[S]

77. Enzyme Kinetics Equation

78. Michaelis-Menten Equation V 0 = V max [S] K m +[S] K2 Km تمایل آنزیم به سوبسترا را نشان می دهد Km کوچک : تمایل بیشتر E به S : سرعت بیشتر تولید P Km بزرگ: تمایل کمتر E به S : سرعت تولید P کمتر

79. Michaelis-Menten kinetics the curve can be described by the equation: → S<< Km → V 0 = V max [S] K m V = K [S] معادله درجه 1 وقتی غلظت سوبسترا کم است واکنش از نوع درجه 1 است : V~ S

80. Michaelis-Menten kinetics the curve can be described by the equation: → Km<< s → V 0 = V max وقتی غلظت سوبسترا زیاد است واکنش از نوع درجه صفر است معادله درجه صفر

81. Michaelis-Menten kinetics the curve can be described by the equation: → S= Km → V 0 = V max 2 Km غلظتی از سوبسترا است که در آن غلظت سرعت واکنش آنزیمی نصف سرعت ماکزیمم باشد

82. The figure is found at: http://fig.cox.miami.edu/~cmallery/255/255enz/gk3x15.gif (December 2006)http://fig.cox.miami.edu/~cmallery/255/255enz/gk3x15.gif K m describes an affinity of the enzyme to its substrate ! indirect proportionality!

83. linearization of the curve: y = k x + q

84. Lineweaver-Burk (double reciprocal plot)

86. Lineweaver-Burk (double reciprocal plot) (cont)

87. Lineweaver-Burk Plot 1 K m 1 V 0 V max [S] V max

89. Measure V o with increasing [S]

90. Different enzymes for different jobs Enzymes involved in breakdown reactions Enzyme and substrate separate Enzyme-substrate complex Enzyme and products separate Enzymes involved in synthesis reactions Enzyme and substrates separate Enzyme-substrates complex Enzyme and product separate

91. Rates of enzyme reactions can be measured by recording the time for a substrate to disappear or a product appears proteinpolypeptides trypsin whiteclear Controlled variables: Volume and concentration of substrate (milk) Volume and concentration of enzyme (trypsin) pH (controlled by buffers) Temperature

92. Enzymes involved in breakdown reactions Catalase Hydrogen peroxideWater + Oxygen Amylase StarchMaltose Lipase Fat Fatty acids + Glycerol Pepsin Protein Amino acids

93. 2.4 Synthesis reactions phosphorylase glucose-1-phosphate starch What is phosphorylase? Phosphorylase is an enzyme that synthesises starch. What is substrate of phosphorylase? Glucose-1-phosphate What is the product? Starch

94. B. Structure of Enzymes

95. Isoenzymes (isozymes) are enzymes which catalyze the same reaction but differ in their primary structure and phyzico chemical properties Isoenzymes are produced by different genes (= true isozymes) or produced by different posttranslational modification (= isoforms) found in different compartments of a cell found in different tissues of an organism can be oligomers of various subunits (monomers)

96. C. How Enzymes Work

97. 97 Properties of enzymes 1)Specificity 專一性 Most enzymes are absolute or near-absolute specific to the substrates - Some enzymes that react with wide range of substrates are peptidises, phosphatases, esterases (bond specific), and hexokinases (group specific) 2)Regulation 調節性 Enzyme activities can be regulated by small ions or small molecules (effectors), such as phosphate or Ca 2+ The regulations are mediated by changing covalent structure

98. 98 S + EESE + P S: ﹝ substrate ﹞ E: ﹝ enzyme ﹞ ES: ﹝ enzyme-substrate complex ﹞ transition state P: ﹝ product ﹞ Highly specific to the substrate of reaction that it catalyzes due to 3-D structure of the folded protein  each enzyme catalyzed only a single type of chemical reaction k1k1 k2k2 k3k3

99. 99

100. 100  affect only the speed, but not energetic or equilibrium of a reaction  Unidirectional  enzyme itself does not change structure after participating rxn; can be used repeatedly

101. 101 Nomenclature of enzymes Some enzyme names are unhelpful to figure the reaction catalyzed, eg. catalase, trypsin, papain…. IUBMB (International Union of Biochemistry and Molecular Biology ) was set up in 1955 Six classes of enzymes ： 1. Oxidoreductase 2. Transferase 3. Hydrolase 4. Lyase 5. Isomerase 6. Ligase

102. 102 The Enzyme Commission number (EC number) a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. EC number system: 4-digit system, ex.: EC 1.2.2.1 1 st number : Class of the enzyme 2nd number : subclass by the type of substrate or the bond cleaved 3rd number : subclass by the electron acceptor or the type of group removed 4th number : serial number of enzyme found Classification based on the chemical reaction catalyzed, not on the source (species or tissues) of the enzyme – Amino acid sequence may be very different

103. 103 Enzyme classification (A) Location of action Endoenzyme: intracellular; most enzymes of the metabolic pathways. Exoenzyme: extracellular; break down (hydrolyze) large food molecules or harmful chemicals. Example: cellulase, amylase, penicillinase.

104. 104 Enzyme classification cont. (B) Presence in cell Constitutive Enzyme: enzymes synthesized by the cell in the absence of any specific stimulus; always present in cell regardless of the amount of substrate; enzymes that are always present and active. Inducible Enzyme: enzymes whose synthesis is stimulated in the presence of a chemical (substrate) or physical stimulus (heat, light); not constantly present in cell and is produced only when the stimulus is present; enzymes that are synthesized or activated when needed.  prevent a cell from wasting energy by making enzymes that will not be used immediately

105. 105 ExoenzymeEndoenzyme Constitutive enzyme Inducible enzyme

106. 106 Enzyme classification cont. (C) Biochemical action: 6 classes; dependon the nature of the reaction catalysed 1. Oxidoreductase : redox reaction; transfer e - or H + from one compound to another. 2. Transferase : transfer functional groups from one substrate to another. 3. Hydrolase : cleave bonds of molecules with addition of water. 4. Lyase: add or remove functional groups from double-bonded substrates. 5. Isomerase : change substrate into its isomeric form. 6. Ligase: formation of bonds so substrates can bind together; also known as synthetases ; need input of ATP and removal of H 2 O.

107. Factors – Substrate Concentration

108. Effect of [Substrate]

109. Enzyme Inhibition

110. 1.Types of Inhibition – Competitive – Folic Acid inhibition by Sulfanilamide competition with PABA – Noncompetitive – Fluoride binding with Ca or Mg atoms in enzymes

112. Inhibition of enzymes

113. Sometimes, a molecule that roughly resembles the normal substrate can fit into the active site, and thereby prevent the enzyme from acting on the substrate. This form of inhibition is called competitive inhibition

114. 1) Competitive inhibition inhibitor resembles substrate it is bound to an active site but not converted by the enzyme increases K m (  afinity of enzyme to its S) if concentration of a substrate is increased the inhibition is decreased the inhibition is reversible

115. Competitive Inhibition

117. Reversible Competitive Inhibition

118. . In non-competitive inhibition, the inhibitor molecule binds to a site other than the active site of the enzyme, and thereby changes the 3-dimensional structure sufficiently to prevent the normal subsrate from fitting into the active site. This is sometimes called allosteric inhibition.

119. Noncompetitive Inhibitor

120. inhibitor binds at a site other than the substrate-binding site inhibition is not reversed by increasing concentration of substrate (no K m change) V max is decreased (it is related to decreasing of active enzyme concentration) reversible only if the inhibitor is not bound by covalent bond 2) Noncompetitive inhibition

121. Non-Competitive Inhibition

123. Uncompetitive Inhibitor

124. Irreversible Inhibitor: Allopurinol

125. The figure is found at: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/EnzymeKinetics.html (December 2006)http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/EnzymeKinetics.html Summary of the inhibition

126. Some enzymes can be inhibited also by an excess of their substrate The figure is found at: http://www-biol.paisley.ac.uk/Kinetics/chapter_3/chapter3_6_1.html (December 2006)http://www-biol.paisley.ac.uk/Kinetics/chapter_3/chapter3_6_1.html

127. The figure is adopted from the book: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, 1997. ISBN 0 ‑ 471 ‑ 15451 ‑ 2 Allosteric enzyme: a) monomeric, b) oligomeric

128. The figure is adopted from the book: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, 1997. ISBN 0 ‑ 471 ‑ 15451 ‑ 2 Allosteric enzyme in T and R conformations: modulators shift the equilibrium inhibitors have a greater affinity for T-state activators and substrates have a greater affinity for R-state

129. Inhibition by drugs and poisons a) reversible b) irreversible  inhibitor is bound covalently into the active site of enzyme

130. Inhibition as a regulation of metabolic pathways: inhibition by products or intermediates: a) feedback regulation b) cross-regulation c) feedforword regulation inhibition by d) reversible covalent modification (e.g. phosphorylation / dephosphorylation)

131. Allosteric regulation activator is „a positive modulator“ inhibitor is „a negative modulator“ The figure is found at: http://www-biol.paisley.ac.uk/Kinetics/Chapter_5/chapter5_2_2.html (December 2006)http://www-biol.paisley.ac.uk/Kinetics/Chapter_5/chapter5_2_2.html ! the curve of allosteric enzymes is sigmoidal not hyperbolic !

132. Inhibition of enzymes used in the regulation is either competitive (K m is increased above substrate concentration within a cell) or allosteric (by conformational changes affecting the catalytic site)

133. Determination of enzyme activity for diagnostic purposes most often blood is investigated (serum, plasma)  evaluation of presence and seriousness of a tissue damage units:  kat/L (= catalytical concentration of enzyme) kat = katal 1 katal = 1 mole of a substrate transformed per 1 sec 1  kat = 10 -6 kat

134. 3. Enzyme Classification – Based on where the enzyme activity occurs. – Exoenzymes – Endoenzymes

135. Endogenous enzymes Digestion: For example during digestion, intestinal cells produce alimentary enzymes, which split the food into such small molecules so they can be absorbed into the blood. These enzymes include Trypsin, Chymotrypsin, Amylase, Lipases, Pepsin, Sucrase, Maltase, etc. Inflammation: During an inflammation, proteolytic enzymes are produced by neighbouring cells, so that the blood clotting process can happen and to remove destroyed tissue. Different enzymes are involved in the process: the enzyme Thrombin, which is important for blood clotting or Elastase, a proteolytic enzyme, involved in tissue degradation

136. Exogenous Enzymes Ingested enzymes (from plants, animals, bacteria and fungi) are absorbed in a small amount of our gut and attain the blood, where they have some effects. It is therefore not amazing that treatment with enzymes is used since thousands of years in different cultures – even nobody knows how it works.

138. جواب 4 پیوند آنزیم با سوبسترا از چه نوع است : 1.پیوند هیدروفوب 2.پیوند هیدروژنی 3.پیوند الکترواستاتیک 4.هر سه مورد

139. جواب 1 کدام عبارت درست است : 1.مکان فعال آنزیم ساختمان سه بعدی دارد 2.مکان فعال انزیم قسمت اعظم ساختمان آنرا تشکیل می دهد 3.تمام کوانزیم ها به مکان فعال با پیوند محکم متصل می شوند 4.تمام کوانزیم ها به مکان فعال با پیوند ضعیف متصل می شوند

140. جواب 1 آنزیمی که واکنش زیر را کاتالیز می کند از چه نوع است : 1.ترانسفراز 2.لیاز 3.هیدرولاز 4.ایزومراز فسفو کراتین کراتین ATPADP

141. جواب 1 کدام عبارت درست است : 1.مکان فعال آنزیم ساختمان سه بعدی دارد 2.مکان فعال انزیم قسمت اعظم ساختمان آنرا تشکیل می دهد 3.تمام کوانزیم ها به مکان فعال با پیوند محکم متصل می شوند 4.تمام کوانزیم ها به مکان فعال با پیوند ضعیف متصل می شوند CH3-CO-S-C