Metabolic Pathways in Higher Plants, Assignments of Pharmacognosy

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Metabolic pathways in Higher Plants

Partha Pratim Das Assistant Professor Department of Pharmacognosy Bengal School of Technology Sugandha, Hooghly, WB Module 1 1

• The metabolism products that are produced during the growth phase of an organisms

in order to perform the physiological functions and supports in overall development of

the cell are called primary metabolites.

• Also known as Trophophase
  • The end products of primary metabolism that are synthesized after the growth phase

has been completed and are important in ecological and other activities of the cell are

known as secondary metabolites.

• Also known as Idiophase Introduction 2

4 Index:

• What is Metabolite
• Types of metabolite
• Primary Metabolite
• Secondary Metabolite
• Shikimic acid pathway
• Precursors of Shikimic acid pathway
• Intermediates of Shikimic acid pathway
• End products of Shikimic acid pathway
• Role of Shikimic acid Pathway

• The metabolism products that are produced during the growth phase of an organisms

in order to perform the physiological functions and supports in overall development of

the cell are called primary metabolites.

Also known as Trophophase

• The end products of primary metabolism that are synthesized after the growth phase

has been completed and are important in ecological and other activities of the cell are

known as secondary metabolites.

Also known as Idiophase.

Metabolic pathway: A series or sequence of chemical reaction which is catalysed by

the enzyme in the living cells. It is a biosynthetic process.

Metabolite: Metabolite is an intermediate or end product of metabolism.

7 Steps of glycolysis: [1] https://www.expii.com/t/glycolysis-cellular-respiration-summary-steps- 10136

8 https://microbenotes.com/pentose-phosphate-pathway/

Pentose phosphate pathway

[2]

• In this reaction requires nicotinamide adenine dinucleotide (NAD) as a cofactor, the enzymetic mechanism regenerates it, resulting in the net use of no NAD. DAHP synthase: 3 - Deoxy-D-arabinoheptulosonate 7- phosphate synthase DHQ Synthase: 3-dehydroquinate synthase

• NADPH as a cofactor
• NADPH as a cofactor

• Claisen rearrangement
• Prephenate is oxidatively decarboxylated with retention of the hydroxyl group by Prephenate dehydrogenase to give p- hydroxyphenylpyruvate, which is transaminated using glutamate as the nitrogen source to give tyrosine and α - ketoglutarate.

Role of ShikimicAcidPathway:

• Shikimic acid is a precursor to the aromatic amino-acids, phenyl-alanine and tyrosine.
• Starting Point in The Biosynthesis of Some Phenolics Phenyl alanine and tyrosine are the precursors used in the biosynthesis of phenylpropanoids. The phenylpropanoids are then used to produce the flavonoids, coumarins, tannins andlignin.
• Gallic acid is formed from 3 - dehydroshikimate by the action of the enzyme shikimate dehydrogenase to produce 3 , 5 - didehydroshikimate. The latter compound spontaneously rearranges to gallic acid.
• Higher plants also possess a mechanism to convert quinic acid to shikimic acid and phenylalanine and tyrosine. Aromatic acids are derived from prephenic acid, which is transformed to phenylpyruvic and p - hydroxyphenyl-pyruvic acids, and afterwards to phenylalanine and tyrosine, respectively.
• Shikimate-U-^14 C gives rise to tryptophan and gramine in young barley seedlings in the light.
• Inhibition of EPSPS causes a deficiency in the aromatic amino acids of plants that ultimately leads to death of plants. ( 5 - enolpyruvylshikimate 3 - phosphate synthases).

• What is Mevalonic acid pathway
• What are the intermediates
• What are the end products (secondary metabolites)
• Role of Mevalonic acid pathway

17

• General pathway

19

Produce:

• Contribute 1/ rd

known secondary metabolites

• Biosynthesis 5 carbon building blocks called Isopentyl Pyrophosphate (IPP) and

Dimethylallyl Pyrophosphate (DMAPP).

• Produce Isoprene molecule and Steroid molecule

20

• Isoprene molecule: (^) • Isoprene linkage:
  • Steroid molecule: