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Alkaloid 질소 함유 식물성분으로 Biogenic Amine 을 제 외한 것임. 질소 함유 식물성분으로 Biogenic Amine 을 제 외한 것임. 아미노산의 최종 대사 산물로 Polyketide, Peptide, Terpenoid 등과 함께 생합성 됨. 아미노산의.

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Presentation on theme: "Alkaloid 질소 함유 식물성분으로 Biogenic Amine 을 제 외한 것임. 질소 함유 식물성분으로 Biogenic Amine 을 제 외한 것임. 아미노산의 최종 대사 산물로 Polyketide, Peptide, Terpenoid 등과 함께 생합성 됨. 아미노산의."— Presentation transcript:

1 Alkaloid 질소 함유 식물성분으로 Biogenic Amine 을 제 외한 것임. 질소 함유 식물성분으로 Biogenic Amine 을 제 외한 것임. 아미노산의 최종 대사 산물로 Polyketide, Peptide, Terpenoid 등과 함께 생합성 됨. 아미노산의 최종 대사 산물로 Polyketide, Peptide, Terpenoid 등과 함께 생합성 됨. 주로 염기성이나 중성 또는 약산성의 Alkaloid 도 있음. 주로 염기성이나 중성 또는 약산성의 Alkaloid 도 있음. 대부분 강한 생리 활성이 있으며, 식물의 방어 물질 또는 최종 대사산물로 추정. 대부분 강한 생리 활성이 있으며, 식물의 방어 물질 또는 최종 대사산물로 추정.

2 Biosynthesis of Amino Acid 식물은 20 개의 필수 아미노산을 스스로 생합성함

3 Amino Acid Biosynthesis Nitrogen Fixation is the process by which atmospheric nitrogen (N 2 ) is captured by certain organisms and converted into NH 3, a form of nitrogen that can be used by all organisms. Nitrogen Fixation is the process by which atmospheric nitrogen (N 2 ) is captured by certain organisms and converted into NH 3, a form of nitrogen that can be used by all organisms. Just as carbon fixation can be performed by only certain organisms (eg. photosynthetic), nitrogen fixation is performed only by a small number of bacterial species, including symbiotic bacteria (Rhizobium) in the roots of leguminous plants. Just as carbon fixation can be performed by only certain organisms (eg. photosynthetic), nitrogen fixation is performed only by a small number of bacterial species, including symbiotic bacteria (Rhizobium) in the roots of leguminous plants. As you might predict, the reduction of N 2 to NH 3 is a highly endergonic process (see Figure 13.1): As you might predict, the reduction of N 2 to NH 3 is a highly endergonic process (see Figure 13.1):

4  Nitrogen fixation is catalyzed by a nitrogenase complex  Electrons (& energy from reduction potential) are derived from 4 NADH  At least 16 ATP must be hydrolyzed  The ammonia (NH 3 ) produced is either utilized by the nitrogen-fixing bacteria, or secreted into the environment  In the case of symbiotic nitrogen-fixing bacteria, the NH 3 is transported into adjacent host cells (where it is used in glutamine synthesis)  Note that a byproduct of nitrogen fixation is hydrogen gas (H 2 )

5 Amino Acid Biosynthesis Amino Acid Biosynthesis: Most prokaryotes, many simple eukaryotes, and plants can synthesize all 20 amino acids used in protein synthesis from simple organic precursors and metabolic intermediates Most prokaryotes, many simple eukaryotes, and plants can synthesize all 20 amino acids used in protein synthesis from simple organic precursors and metabolic intermediates Mammals and other animals can only synthesize a subset of these amino acids; known as the 12 "nonessential" amino acids (see Table 14.1) Mammals and other animals can only synthesize a subset of these amino acids; known as the 12 "nonessential" amino acids (see Table 14.1)  The remaining amino acids (8 "essential" amino acids) must be obtained from the diet  this explains one of the primary reasons for the requirement of protein in the diet

6  "Complete" proteins contain adequate amounts of all the essential amino acids  generally derived from animals (meat, milk, eggs)  "Incomplete" proteins are deficient in one or more of the essential amino acids  generally derived from plants  examples: beans (low in methionine), cereal grains (low in lysine), corn protein (low in lysine & tryptophan), wheat protein (low in lysine)

7 Glutamate Family Glutamate (glutamic acid) is derived from  -ketoglutarate, an intermediate in the Krebs Cycle, through direct incorporation of ammonium (NH 4 + ): Glutamate (glutamic acid) is derived from  -ketoglutarate, an intermediate in the Krebs Cycle, through direct incorporation of ammonium (NH 4 + ): Glutamine is derived from glutamate through direct incorporation of ammonium (NH 4 + ): Glutamine is derived from glutamate through direct incorporation of ammonium (NH 4 + ):

8 Proline and arginine are derived from glutamate through two very different biosynthetic pathways. Proline and arginine are derived from glutamate through two very different biosynthetic pathways.  Proline is synthesized through reduction of the carboxylic acid in the side chain of glutamate Many amino acid biosynthetic pathways involve transamination reactions: Many amino acid biosynthetic pathways involve transamination reactions:  The  -amino group from one amino acid is transferred to an  -keto acid to produce a new amino acid  Glutamate is a primary amino group donor in these reactions (see serine biosynthesis below):

9 Serine Family Serine is derived from 3-phosphoglycerate (glycerate-3- phosphate), an intermediate in the energy-yielding phase of glycolysis, through a series of reactions that include transamination (with glutamate as the amino group donor): Serine is derived from 3-phosphoglycerate (glycerate-3- phosphate), an intermediate in the energy-yielding phase of glycolysis, through a series of reactions that include transamination (with glutamate as the amino group donor):

10 Glycine is derived from serine by removal of the hydroxymethyl group from the side chain: Glycine is derived from serine by removal of the hydroxymethyl group from the side chain: Asparagine is derived from glutamine through a transamination reaction (the amino group is derived from the glutamine side chain, rather than the  -amino group): Asparagine is derived from glutamine through a transamination reaction (the amino group is derived from the glutamine side chain, rather than the  -amino group):

11 Pyruvate Family Alanine is derived from pyruvate, the end product of glycolysis, through a transamination reaction (with glutamate as the amino group donor): Alanine is derived from pyruvate, the end product of glycolysis, through a transamination reaction (with glutamate as the amino group donor): Histidine Biosynthesis Histidine is synthesized through a complicated biosynthetic pathway that involves the production of phosphorylated nucleoside intermediates Histidine is synthesized through a complicated biosynthetic pathway that involves the production of phosphorylated nucleoside intermediates

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13 Alkaloids: Introduction small organic molecules (secondary metabolites) of plants which contain nitrogen (ussually in a ring) alkaloids, protoalkaloids, pseudoalkaloids structurally diverse: 12,000+ structures 20% of all plant species concentrated in specific plant taxa (families, genera, species) biosynthetically diverse (families/types) strong biological effects (-> 3 ecological examples)

14 Historical and human importance: pharmaceutically significant (often neurological) effect of N biological effects & uses: analgesic - pain killers (morphine)   paralysis, anesthesia (tubocurarine, coniine)   stimulants (caffeine, nicotine)   antitussive (codeine)   emetic (emetine)   anti-cancer drugs (taxol, vinblastine)   toxins and antibiotics (quinine, sanguinarine)

15 Alkaloid Families and Biosynthesis families classified by ring structure derived from amino acids [with a few exceptions] Examples:   tyrosine -> morphine (opium alkaloids)   tryptophan -> quinine (quinoline)   vinblastine (indole)   glutamate (via ornithine) -> cocaine (tropane) - >nicotine (tobacco alk) - > senecionine (pyrrollizidine)   aspartate -> nicotine   xanthine -> caffeine, theobromine (purine)

16 General Features of Alkaloid Biosynthesis can have complex structures, many biosynthetic steps & compartments (eg) vinblastine   often found in mixtures of related compounds pathway begins with decarboxylation (eg) tyr -> tyramine may include other components - (eg) vinblastine, (dimeric indole terpenoid) solanidine (tripterpene alkaloids of potato) organ specific synthesis and storage (bark, roots, flowers) sequestered within cells and special structures (vacuole, latex vesicles, idioblasts, epidermis)

17 Biosynthesis of Alkaloid

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35 Steroid Alkaloid the Solanum type - one example is solanidine. This steroid alkaloid is the nucleus (i.e. aglycone) for two important glycoalkaloids, solanine and chaconine, found in potatoes. Other plants in the Solanum family including various nightshades, Jerusalem cherries, and tomatoes also contain solanum-type glycoalkaloids. Glycoalkaloids are glycosides of alkaloids. the Solanum type - one example is solanidine. This steroid alkaloid is the nucleus (i.e. aglycone) for two important glycoalkaloids, solanine and chaconine, found in potatoes. Other plants in the Solanum family including various nightshades, Jerusalem cherries, and tomatoes also contain solanum-type glycoalkaloids. Glycoalkaloids are glycosides of alkaloids.solanidinesolanine and chaconinesolanidinesolanine and chaconine the Veratrum type. There are more than 50 Veratrum alkaloids including veratramine, cyclopamine, cycloposine, jervine, and muldamine occurring in plants of the Veratrum spp. The Zigadenus spp., death camas, also produces several veratrum- type of steroid alkaloids including zygacine the Veratrum type. There are more than 50 Veratrum alkaloids including veratramine, cyclopamine, cycloposine, jervine, and muldamine occurring in plants of the Veratrum spp. The Zigadenus spp., death camas, also produces several veratrum- type of steroid alkaloids including zygacineveratraminecyclopamine, cycloposine, jervine, and muldaminezygacineveratraminecyclopamine, cycloposine, jervine, and muldaminezygacine

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38 Summery of Alkaloids very toxic plant chemicals in common plant species toxic chemicals in food plants effective against generalist insects, but specialists have counteradapted many alkaloids have documented multiple effects on different targets   neurotransmitter receptors (nicotine, cocaine, morphine)   neurotransmitter transport/degradation (cocaine)   interfere with cytoskeleton (tubulin - taxol)   ion channels (caffeine)   enzyme inhibitors (caffeine, theobromine)

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