briefly describe enzyme and coenzyme and its role in many orders. Consist of enzyme nomenclature, enzyme part: prosthetic group, metalions, cofactors, and secondary substrate. Describe inhibition action.

1. Enzyme and Coenzyme
Pramono,H.

4. What will we learn?
• Foreword
• Nomenclature
• Activation
• Inhibition and mechanism of inhibition
• Factor that affect enzymes activity

5. Foreword
• Enzyme are proteins (or RNA) with powerful
catalytic activity thus called biocatalysator
• Synthesized by biological cells and in all organism,
they are involved in chemical reactions related to
metabolism
• Alcoholic, ripening, aging of meat, etc.
• Enzymes play a role in food science

6. Catalysis
• Catalyst is substance that increase reaction
without consumed by the reaction
• Feature of catalyst
– Lowers the activation energy needed to start a
reaction
– Is not used up during the reaction
– Is unchanged after a reaction

8. Reaksi dengan dan tanpa enzim

10. Nomenclature
• Enzyme classified based on type and
mechanism of reaction
• Old time: based on hydrolysis of covalent
bond
– Protease, lipase, amylase, etc.
• In one substrate can occur other reaction, not
only hydrolysis
• Now: enzyme classified based on type and
mechanism of reaction

11. IUB nomenclature system
• International Union of Biochemistry
1. Reaksi dan enzim yang mengatalisis enzim tersebut
membentuk enam kelas, masing-masing mempunyai
4-13 sub kelas
2. Nama enzim terdiri atas dua bagian, nama pertama
menunjukkan substrat dan nama kedua yang berakhiran
ase menyatakan tipe reaksi yang dikatalisis
3. Informasi tambahan, bila diperlukan untuk menjelaskan
reaksi dapat dituliskan dalam tanda kurung di bagian
akhir
4. Enzim memiliki EC yang mencirikan tipe reaksi ke dalam
reaksi (digit pertama), subkelas (digit kedua),
subsubkelas (digit keempat)

12. Based on EC
1. EC 1 Oksidoreduktase: mengatalisis reaksi
oksidasi/reduksi
2. EC 2 Transferase: mentransfer gugus fungsi
3. EC 3 Hidrolase: mengatalisis hidrolisis berbagai
ikatan
4. EC 4 Liase: memutuskan berbagai ikatan kimia selain
melalui hidrolisis dan oksidasi
5. EC 5 Isomerase: mengatalisis isomerisasi sebuah
molekul tunggal
6. EC 6 Ligase: menggabungkan dua molekul dengan
ikatan kovalen

13. Example
Alchohol dehidrogenase
Substrate
Reaction catalyst by enzyme

14. Mechanism LOCK AND KEY

15. Enzyme cofactors
• Rigorous analysis has demonstrated that
numerous enzymes are not pure proteins
• They can contain metal ions and/or low
molecular weight nonprotein organic
molecules
• These nonprotein hetero constituents are
denoted as cofactor which are indispensable
for enzyme activity

16. Systematics of cofactor-containing enzymes
Holo-enzyme
Cofactor Apoenzyme
Metalions Coenzyme
Proeshetic group Cosubstrate
Stable binding Cyclic regeneration
Involved in reaction

18. Metalions
• Metalions commonly called cofactor
• Function:
– Stabilizers of enzyme conformation
– Direct participation in catalysis
• Located in active site
• Common metal ions:
– Magnesium, calcium and zinc
– Iron, Copper, and molybdenum

19. Hexokinase
www.kek.jp

20. Nature review microbiology
Nitrogenase

21. Prosthetic group
• Flavin
• Hemin
• Pyridoxal phosphate

22. Flavin
• Riboflavin known as Vit. B2 is the building
block of flavin mononucleotide (FMN) and
Flavin adenine dinuleotide (FAD)
• Both act as prostetic groups for electron
transfer reactions in number of enzymes

24. Hemin
• Peroxidases from food of plant origin and
several catalases contain ferri-protoporphyrin
IX
• Chromophore responsible for the brown color
of the enzymes
• In catalytic reactions there is a change in the
electron excitation spectra of the peroxidases

25. Peroxidase

26. Pyridoxal phosphate
• Pyridoxal phosphate are designated as
vitamin B6 and are essential ingredients of
food
• Coupled to the enzyme as a prosthetic group
through a lysyl residue, involved in
conversion reactions of amino acids

27. Structure of prosthetic group Vit.B6

28. Role of Vitamin as prosthetic group
www.chemistryexplained.com

29. Cosubstrate
• Consist of NAD and ATP
• Nicotinamide adenine dinucleotide (NAD+)
– Transhydrogenase (e.g. lactate dehydrogenase,
alcohol dehydrogenase) dehydrogenate or
hydrogenate their substrates with the help of
pyridine cosubstrates
– NAD residue accepts or donate a hydride ion (H-)

31. Theory of Enzyme Catalysis
• Active site
– Small part of enzyme where reaction of catalysis
occurs
– Enzyme molecule is often larger in size by a
factor of several orders of magnitude
– Prove: Glucose oxydase (Mr= 150,000) which
glucose (Mr=180)

32. Substrate binding
• Stereospecificity
– Before being bound to the binding locus, the
substrates are distinguished by their cis-, trans-
isomerism and by their optical antipodes
• Lock and key hypothesis
– E. Fisher
• Induced-fit model
– The active site can ‘move’ to get correct position
before catalysis reaction occurs

33. Factors that affect enzyme reaction
• Temperature
• pH
• Inhibitors

34. Temperature
• Remind that enzyme is consist of protein?
• Denaturation
• But every enzyme has it own characteristic,
regarding to its sulfide bond (or cystein bond):
– Low amount of sulfide bond sensitive to higher
temperature
• Trypsin  denaturated in 95oC
– High amount of sulfide bondTaq Polymerase
still active in 95oC

36. pH
• pH affect 3D conformation of enzyme
• Different enzyme different optimum pH

37. Enzyme inhibition
• Reversible
– Enzyme show it activity after inhibitor released
• Irreversible
– Total damage

38. Diisopropyl
fluorophosphate (DFP)
react with serine protease
Reversibel Irreversibel

39. Reversible inhibition
• Competitive inhibition
• Uncompetitive inhibition,
• Mixed inhibition
• Non-competitive inhibition
• Feedback inhibition

40. Competitive inhibition

43. Feedback inhibition

44. Thank you
@heruiwak