Biochemistry

Refers to a natural process converting atmosphericnitrogen to ammonium to yield usable nitrogen source.• Only a few prokaryotic species can "fix" nitrogen.• Nitrogenase complex dinitrogenasedinitrogenase reductase
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BiochemistrySubject: BiochemistryInstructor: MSc. Le Hong PhuDay: 2 P eriod: 1234Semester 2 Academic year: 2009-2010Group 4 GROUP MEMBERSNguyễn Thị Thúy Giang BTIU08047Chung Thế Hào BTUN08015Lại Nguyên Huy BTIU08015Nguyễn Quang Huy BTWE08012Đặng Xuân Khải BTIU08019Dương Bá Phú BTIU08058Trần Triệu Quân BTUN08027Đường Thị Kiều Trang BTWE08Huỳnh Hải Vân BTIU08 OUTLINEI. IntroductionII. Body 1. Nitrogen fixation 2. Transamination reaction and incorporation of ammonium 3. Biosynthesis of amino acids i. Glutamate ii. Aspartate iii. Serine iv. Pyruvate v. Aromatic vi. Histidine4. One carbon metabolism5. Amino acids as metabolic precursor i. Glutathione ii. Alkaloid iii. Nucleotides iv. Heme group6. Regulation of amino acid biosynthesisIII. Conclusion INTRODUCTIONWHY CARES? Nitrogenous compounds are prevalent. Nitrogenous compounds are metabolic important  Determine our health. Human alone cannot synthesize all these compoundsWHAT WE FOCUS?The “build up” of nitrogenous compounds (monomeronly): amino acids and more.Only some forms of nitrogen are accessibleThe biosynthesis pathways are extensively diverse.Nitrogen balance:Positive: intake > loss  childhood, pregnancy, illnessrecovery.Negative : intake < loss  Malnutrition.Neutral: intake = loss  adulthood. NITROGEN FIXATION• Refers to a natural process converting atmosphericnitrogen to ammonium to yield usable nitrogen source.• Only a few prokaryotic species can fix nitrogen.• Nitrogenase complex dinitrogenase dinitrogenase reductaseDinitrogenase: – Referred to as Fe-Mo protein. – Heterotetramerous, containing two Mo atoms, and 30 iron atoms. – Catalyze the reaction: N2 + 8H+ + 8e-  2NH3 + H2Dinitrogenase reductase: – Referred to as Fe protein. – is a dimer – Carry electrons from ferrodoxin and integrate with ATPs.16 ATPs are spent to reduce a N2 to 2 NH3 expensive TRANSAMINATION • Reaction involving transferring an α amino group from an α amino acid and an α keto acid. • 2 typical α-keto acids : α-ketoglutarate, pyruvate (carbonyl group is directly adjacent to carboxyl group). O H O H O O O O + R2 O- + C C O→ - - C C R1 C O CR2 O- C C ←R1 NH3+ NH3+ Donor amino acid New keto acid New amino Acceptor acid keto acid REVERSIBLE• Transamination occurs in eukaryotic cells (aminotransferases) and can be found in cytoplasm or mitochondria.• Aminotransferase possesses 2 types of specificity: – α-amino acid donate α-amino group. – α-keto acid accept α-amino group.• Most of aminotransferases use glutamate as amino group donor.• Glutamate is produced when α-ketoglutarate accept an amino acid group. α-ketoglutarate and glutamate pair play an important role in metabolism of amino acid.Vitamin B6 is a cofactor of aminotransferases H H N+ HHO C Enzyme O + OHR C C C O- αβ O- P O H NH3+ O- N+ CH 3α-amino acid H H2O ↑↓ Pyridoxal phosphate H2O H HO R C C C O- βα H N+ HC H O O- O- P O Schiff base O- N+ C H3 H H+ ↑↓ H + H O H O C C O- ...