BIOKIMIA

1. Protein BIOKIMIA BIOKIMIA

2. Protein • Protein terbentuk atas beberapa AA, hampir semua AA memiliki karbon asimetrik (α-karbon) yg mengikat 4 gugus yaitu: • Karboksil • Amino • R • hidrogen BIOKIMIA

3. R NH3+ C COO- H Amino acid: Basic unit of protein Different side chains, R, determin the properties of 20 amino acids. Amino group Carboxylic acid group An amino acid

4. 20 Amino acids Leucine (L) Isoleucine (I) Valine (V) Alanine (A) Glycine (G) Proline (P) Asparagine (N) Methionine (M) Tryptophan (W) Phenylalanine (F) Tyrosine (Y) Threonine (T) Serine (S) Cysteine (C) Glutamine (Q) Histidine (H) Glutamic acid (E) Arginine (R) Asparatic acid (D) Lysine (K) White: Hydrophobic,Green: Hydrophilic,Red: Acidic,Blue: Basic

5. Lanjutan • AA dianalisis menggunakan AAA, dg syarat diketahui polaritasnya sekaligus dilihat kandungan gugus R, pH=7 • Gugus R sama sekali tdk polar (hidrofobik), cont.alanin, fenilalanin, triptofan • Gugus R sangat polar (hidrofilik), cont.sistein,tirosin BIOKIMIA

6. Lanjutan 3. AA gugus R bermuatan negatif (asam), cont.as.aspartat, as.glutamat 4. AA gugus R bermuatan positif (basa), cont.histidin, arginin BIOKIMIA

7. Karakteristik AA • Zwitter ion (ion ganda), bisa bermuatan positif & negatif • Bipolar, bisa berperan sebagai asam dan basa BIOKIMIA

8. Asam Amino • AA merupakan pembentuk protein yg terikat pd ikatan polipeptida. • Ciri khas protein akan mengikuti ciri khas AA pembentuknya. BIOKIMIA

9. Lanjutan • Berdasarkan gugus & rumus bangun AA terbagi atas: • Alifatic side chain; glisin, alanin, valin • Hydroxylic side chain; threonin • Carboxylic side chain; amida • Aromatic side chain; as.glutamat • Sulfur containing side chain; metionin • Basic side chain; arginin,lisin • Imino acid side chain; prolin,hydroxyprolin BIOKIMIA

10. Bentuk &Sifat Fisik Protein BIOKIMIA

11. 1. GLOBULAR • Berbentuk bulat • Rantai berlipat-lipat • Larut dlm sistem larutan termasuk air & mudah terdifusi CONTOH: Insulin;hemoglobin;enzim;antibodi BIOKIMIA

12. 2.SERABUT • Rantai polipeptida panjang, memanjang pd satu sumbu • Peranannya bersifat struktural & pelindung CONTOH: Hair;wool;nails;skin BIOKIMIA

13. Bentuk &Struktur Protein BIOKIMIA

14. Primary Structure of Proteins The particular sequence of amino acids that is the backbone of a peptide chain or protein Ala-Leu-Cys-Met

15. Proteins are linear polymers of amino acids R1 R2 COOー COOー NH3＋ NH3＋ ＋ ＋ C C H H A carboxylic acid condenses with an amino group with the release of a water H2O H2O R1 R2 R3 C C CO CO C CO NH3＋ NH NH Peptide bond Peptide bond H H H The amino acid sequence is called as primary structure D F T A A S K G N S G

16. Secondary Structure – Alpha Helix • Three-dimensional arrangement of amino acids with the polypeptide chain in a corkscrew shape • Held by H bonds between the H of –N-H group and the –O of C=O of the fourth amino acid along the chain • Looks like a coiled “telephone cord”

17. Secondary Structure – Beta Pleated Sheet • Polypeptide chains are arranged side by side • Hydrogen bonds form between chains • R groups of extend above and below the sheet • Typical of fibrous proteins such as silk

18. Secondary Structure – Triple Helix • Three polypeptide chains woven together • Glycine, proline, hydroxy proline and hydroxylysine • H bonding between –OH groups gives a strong structure • Typical of collagen, connective tissue, skin, tendons, and cartilage

19. Basic structural units of proteins: Secondary structure α-helix β-sheet Secondary structures, α-helix and β-sheet, have regular hydrogen-bonding patterns.

20. Tertiary Structure • Specific overall shape of a protein • Cross links between R groups of amino acids in chain disulfide –S–S– + ionic –COO– H3N– H bonds C=O HO– hydrophobic –CH3 H3C–

21. Quaternary Structure • Proteins with two or more chains • Example is hemoglobin Carries oxygen in blood Four polypeptide chains Each chain has a heme group to bind oxygen

22. Three-dimensional structure of proteins Tertiary structure Quaternary structure

23. Hierarchical nature of protein structure Primary structure (Amino acid sequence) ↓ Secondary structure （α-helix, β-sheet） ↓ Tertiary structure （Three-dimensional structure formed by assembly of secondary structures） ↓ Quaternary structure （Structure formed by more than one polypeptide chains）

24. Berdasar ik.peptida &ik.lainnya • PROTEIN SEDERHANA Yaitu hanya mengandung α-AA saja Cont. Albumin, globulin,glutein,histon 2. PROTEIN KONJUGASI Yaitu disamping mengandung AA jg komponen lain yg jika dihidrolisa menghasilkan gugus yg dinamakan gugus prostetik Cont.lipoprotein,glikoprotein,metaloprotein BIOKIMIA

25. Fungsi Protein BIOKIMIA

26. Fungsi Biologis protein • ENZIM; tripsin, lipase,protease • PROTEIN TRANSFER;membawa sesuatu utk proses metabolisme, ex. hemoglobin • NUTRIENT;pembawa zat gizi, ex. kasein • KONTRAKTIL; utk bergerak, ex. Aktin &miosin BIOKIMIA

27. Fungsi Biologis protein • STRUKTURAL; membentuk struktur ex. kolagen • PERTAHANAN; ex. antibodi • PENGATUR (REGULATORY PROTEIN); ex. Insulin (mengatur kadar glukosa dlm darah) BIOKIMIA

28. Lain-lain BIOKIMIA

29. Protein Hydrolysis • Break down of peptide bonds • Requires acid or base, water and heat • Gives smaller peptides and amino acids • Similar to digestion of proteins using enzymes • Occurs in cells to provide amino acids to synthesize other proteins and tissues

30. Hydrolysis of a Dipeptide

31. Denaturation Disruption of secondary, tertiary and quaternary protein structure by heat/organics Break apart H bonds and disrupt hydrophobic attractions acids/ bases Break H bonds between polar R groups and ionic bonds heavy metal ions React with S-S bonds to form solids agitation Stretches chains until bonds break

32. Applications of Denaturation • Hard boiling an egg • Wiping the skin with alcohol swab for injection • Cooking food to destroy E. coli. • Heat used to cauterize blood vessels • Autoclave sterilizes instruments • Milk is heated to make yogurt

33. TERIMA KASIH BIOKIMIA