PENGANTAR ILMU BIOKIMIA Oleh H Mohammad Hanafi MBBS

PENGANTAR ILMU BIOKIMIA. Oleh H. Mohammad Hanafi, MBBS, dr, MS. Dosen Ilmu Biokimia FK UAIR 1

Ilmu Biokimia : mempelajari macam-macam molekul yang ada di dalam sel mahluk hidup dan organisme dan reaksi-reaksi kimia yang terjadi diantara molekul-molekul tersebut. Ilmu Biokimia dapat perkawinan antara ilmu kimia dan ilmu biologi. 2

Ilmu yang memperhatikan (concerned) dengan ilmu kimia dasar dari kehidupan (the chemical basis of life) Two notable breakthroughs in the history of biochemistry (1) Discovery of the role of enzymes as catalysts (2) Identification of nucleic acids as information molecules Flow of information: from nucleic acids to proteins DNA RNA Protein 3

Manusia organ ( otak, mata, organ-organ pencernaan, paru, jantung, ginjal, organ-organ reprodiksi, dan lainnya) Organ jaringan, Jaringan sel 4

Organism, Organ, Cell Organism n Orga 5

The Cell The ER modifies proteins, makes macromolecules, and transfers substances throughout the cell. Nucleus only in eukaryotic cells. Contains most of the cell's genetic material. Ribosome translates m. RNA into a polypeptide chain (e. g. , a protein). Mitochondrion manufactures adenosine triphosphate (ATP), which is used as a source of energy. • circa 100 trillion (1014) cells in a human organism • 200 different forms of cells 6

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Fig 1. 15 (a) Eukaryotic cell (animal) 8

Fig 1. 13 Structure of a biological membrane • A lipid bilayer with associated proteins 9

Sel ada organel, supra molekul (ribosom, enzim), makromulekul (polisakarida, polipeptida), building block (asam amino, glukosa, asam lemak, deoksinukleotida, ribonukleotida dll) metabolit (asam piruvat, asam sitrat, asetoasetil-Ko. A, asam urat dll). 10

Precursor adalah suatu senyawa yang dianggap dapat sebagai tanda adanya kehidupan di suatu planet Bahannya yg dianalisa adalah udara (H 2 O, N 2, CO 2, NH 3 dan O 2) 11

Manusia tersusun atas : (1)bahan organik, protein 15%, lipid 15% dan karbohidrat 5%, (2) bahan anorganik 5% berat badan. (a) kation, Na+, K, Ca 2+, Mg 2+, Fe, Zn 2+, Cu 2+ dll. (b) anion Cl-, HCO 3 -, SO 42 -, H 2 P 2 O 42 - dll. 12

Karbohidrat Senyawa polihidroksi aldehid atau polihidroksi keton. (1). Monosakarida (Cn H 2 n On ): Jumlah atom CAldehid Keton Triose (3) Gliserose Dihidroksi aseton Tetrose (4) Eritrose Eritrulose Pentose (5) Ribose Ribulose Heksose (6) Glukose Fruktose 13

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Disakarida { Cn (H 2 O)n-1 }: Sukrose (glukose dan fruktose) Laktose (glukose dan galaktose) Maltose (dua glukose) 15

(3). Oligosakarida ( 4 – 10 mono sakarida ) (4). Polisakarida: homopolisakarida, amilum, glikogen, innulin, sellulose dan lainnya heteropolisakarida, chitin, glikoprotein dll. 16

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Lipida Senyawa yang larut dalam pelarut nonpolar. (A). Lipida sederhana 1. triasil gliserol 2. lilin (B). Lipida komplek 1. fosfolipid, lesitin (lechitine) 2. serebrosida, sphingosin 3. lipoprotein (C). Turunan lipid 1. asam lemak 2. gliserol 3. steroid 4. keton bodies 18

Asam amino dan Protein Senyawa yang mengandung gugus asam dan amino : H α R-C-N H 3+N-C-COOH | R Asam amino esensial (tikus putih) : Arginine (Arg=R), Histidine (His=H), Isoleucine (Ileu=I), Leucine (Leu=L), Lysine (Lys=K), Phenylalanine (Phe=F), Methionine (Met=M), Threonine (Thr=T), Tryptophan (Try=W) dan Valine (Val=V). 19

Asam amino yang lain : Glycine (Gly=G), Alanine (Ala=A), Serine (Ser=S), Tyrosine (Tyr=Y), Cysteine (Cys=C), Aspartic acid (Asp=D), Asparagine (Asn=N), Glutamic acid (Glu=E), Glutamine (Gln=Q), dan Proline (Pro=P). 20

Name 1 -letter code Triplet Glycine G GGT, GGC, GGA, GGG Alanine A GCT, GCC, GCA, GCG Valine V GTT, GTC, GTA, GTG Leucine L TTG, TTA, CTT, CTC, CTA, CTG Isoleucine I ATT, ATC, ATA Histidine H CAT, CAC Serine S TCT, TCC, TCA, TCG, AGT, AGC Threonine T ACT, ACC, ACA, ACG Cysteine C TGT, TGC Methionine M ATG Glutamic Acid E GAA, GAG Aspartic Acid D GAT, GAC, AAT, AAC Lysine K AAA, AAG Arginine R CGT, CGC, CGA, CGG, AGA, AGG Asparagine N AAT, AAC Glutamine Q CAA, CAG Phenylalanine F TTT, TTC Tyrosine Y TAT, TAC Tryptophan W TGG Proline P CCT, CCC, CCA, CCG Terminator (Stop) * TAA, TAG, TGA 21

Asam amino dapat membentuk polipeptida (protein) dengan ikatan peptida. Pembagian protein : (A). Protein sederhana: albumin, globulin, kollagen, histon da protamin (B). Protein terkonyugasi, nukleoprotein, glikoprotein, lipoprotein, metaloprotein, dan lainnya 22

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Protein Structure n Primary structure is the sequence of the amino acids in the protein. n A change in one amino acid can alter the biochemical behavior of the protein. n Secondary structure is the regular arrangement of segments of protein. 25

Proteins Protein Structure One common secondary structure is the -helix. Hydrogen bonds between N-H bonds and carbonyl groups hold the helix in place. 26

Proteins Protein Structure n Tertiary structure is the three dimensional structure of the protein. n Shape of the protein 27

Tertiary structure of proteins catalase enzyme Structure solved using Xray crystallography 28

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Nucleic Acids n Nucleic acids carry genetic information. n DNA (deoxyribonucleic acids) have molecular weights around 6 - 16 106 amu and are found inside the nucleus of the cell. n RNA (ribonucleic acids) have molecular weights around 20, 000 to 40, 000 amu and are found in the cytoplasm outside the nucleus of the cell. 30

Nucleic acids are made up of nucleotides. There are three important parts to a nucleic acid: 1 phosphoric acid unit, 2 five carbon sugar (e. g. deoxyribose), and 3 nitrogen containing organic base (e. g. adenine). 31

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Adenosine Triphosphate (ATP) • Nitrogenous base (adenine), sugar (ribose) 33

Deoxyadenylic Acid FG 25_030. JPG 34

Structure of a Polynucleotide 35

Nucleic Acids n DNA and RNA have different sugars (dexoyribose vs. ribose). n There are only five bases found in DNA and RNA: n adenine (A), n guanine (G), n cytosine (C), n thymine (T found in DNA only), and n uracil (U found in RNA only). 36

Nitrogen-Containing Bases 37

Nucleic Acids n DNA consists of two deoxyribonucleic acid strands wound together in a double helix. n The phosphate chains are wrapped around the outside of the DNA molecule. 38

• Complementary base pairs are formed from bases which optimize Hbonding: T and A or C and G. • The complementary base pairs are held together by hydrogen bonding. • During cell division, the DNA double helix unwinds. 39

Complementary Base Pairs 40

n A new strand is formed when bases attach to each strand of the unwinding double helix. n Because of the optimized hydrogen bonding, there is only one location for each base. 41

• Therefore, the order of bases in the new strand is the same as the order of bases in the original strand. • This is how genetic information is preserved during cell division • DNA structure provides us with the understanding of how protein synthesis occurs, how viruses infect cells, and other biological problems occur. 42

FG 25_032. JPG DNA Double Helix Wassalamua’alikum Wr. Wb. 43