*2.5.1.2 The pentose phosphate pathway*

It is used to generate NADPH (nicotinamide adenine dinucleotide phosphate) It is to interrupt glucose, break down that can be used by plant. It provides sugar links that delivered as building blocks for nucleic acids and aromatic amino acids.

This pathway is divided into two phases:


#### *2.5.1.3 The shikimate pathway*

It includes the biosynthesis of chorismate, which may later work as a precursor for the biosynthesis of the aromatic amino acids like tyrosine phenylalanine and tryptophan. This pathway was reviewed by Weaver and Herrmann [17] and Hermann and Weaver [18] in biochemistry. It was seen in both plants and microorganisms. Shikimate was synthesized from the substrates erythrose 4-phosphate

**229**

[8, 10].

flavonoids [8, 11].

*2.5.4 Monolignol biosynthesis*

*2.5.5 Lignan biosynthesis*

controlled [10, 11].

*Phenolic Compounds*

amino acids [8, 10–16].

*DOI: http://dx.doi.org/10.5772/intechopen.96740*

*2.5.1.4 The general phenylpropanoid pathway*

transfer to p-coumaric acid [10, 11].

*2.5.3 Biosynthesis of flavonoids and condensed tannins*

*2.5.2 Biosynthesis of phenolic acids*

and phosphoenolpyruvate. By glycolysis and the pentose phosphate pathway, these two precursors are extracted respectively, and by the enzyme DAHP synthase, they are condensed to 3-deoxy-D-arabino-heptulosonate 7- phosphate. This steps end in the formation of 3-dehydroquinate by the enzyme 3- dehydroquinate synthase, 3-dehydroshikimate and 3- dehydroquinate dehydratase, and finally shikimate by the enzyme shikimate dehydrogenase. Shikimate was converted to shikimate 3-phosphate by shikimate kinase, then to 5-enolpyruvylshikimate 3-phosphate by 5-enolpyruvylshikimate 3-phosphate synthase. EPSP is then obtained to chorismate by chorismate synthase. Chorismate is bifurcate tryptophan on the one hand, and phenylalanine and tyrosine on the opposite hand for the biosynthesis of aromatic

It was generating a substratum to phenylpropanoid compounds which includes coumarins, monolignols, hydroxycinnamic acids, flavonoids, stilbenes and sinapoyl esters. This pathway starts with phenylalanine via the shikimate pathway. It catalyzed phenylalanine by the enzyme phenylalanine ammonia lyase (PAL) and ends in cinnamic acid. Later, it was hydroxylated by cinnamic acid 4- hydroxylase (C4H)

Phenolic acids are not abundant in most plants. There are in the form of gallic acid and salicylic acid. Gallic acid may be a precursor for the ellagitannins and gallotannins. Salicylic acid is an important defense property that mediates systemic acquired resistance (SAR), and it is also used as a signaling molecule to relay information on pathogen attack to other parts of the plant. After receiving the SA signal, a defense response is trigger the biosynthesis of pathogenesis-related (PR) proteins

In the process of flavonoid biosynthesis, the identification and isolation of genes by the flavonoids which are a colored compound. Mutant phenotypes are identifiable from variation in color easily. The flavanonols can converted to

They are synthesized from pcoumaroyl-CoA via the shikimate and phenylpropanoid pathways and are the component of lignans and lignin, and some of them are serve as precursors for sinapoyl esters and hydroxycinnamic acids [8, 10, 11].

In this process, the oxidative coupling of monolignol radicals are synthesized. *The monolignol radicals are generated through the action of laccases or peroxidases*. Lignans are active, and a typical pair of chemical compound which is present in some species and it binds in between the monolignols [regio-chemical control], thereby both the coupling sites and their position of the 2 monomers are

anthocyanins. Condensed tannins transformed from polymerization of

#### *Phenolic Compounds DOI: http://dx.doi.org/10.5772/intechopen.96740*

*Bioactive Compounds - Biosynthesis, Characterization and Applications*

Data of the purified recombinant proteins obtained from in-vitro assays can be interpreted much easily than data of crude or partially purified protein extracts that

2.No enzymes present which convert the enzyme of interest, and it reduce the

The carbohydrates for plants are acquired from photosynthesis process from the atmosphere, a fixed CO2 is converted to carbohydrates from sunlight. The photosynthesis process within the cell for carbon-based metabolites including phenolic compounds helps the carbohydrates to form the building blocks. The two catabolic processes are the precursors of plant phenolic compounds within the plant cell. This includes many pathways such as glycolysis, pentose phosphate, phenylpropanoid

It is also known as Embden-Meyerhof-Parnas pathway, carbohydrates generated during photosynthesis from the catabolic process are broken into pyruvate, and

It is used to generate NADPH (nicotinamide adenine dinucleotide phosphate) It is to interrupt glucose, break down that can be used by plant. It provides sugar links

2.Oxidization for hexoses to urge ATP reductant, and pyruvate [10–14].

that delivered as building blocks for nucleic acids and aromatic amino acids.

1.Oxidative phase: In this phase, the glucose-6-phosphate is converted to

2.Non-oxidative phase: in this phase, by reversible reactions two pentose-phosphate residues are transform to sugar- phosphate molecules [8, 10–13].

It includes the biosynthesis of chorismate, which may later work as a precursor for the biosynthesis of the aromatic amino acids like tyrosine phenylalanine and tryptophan. This pathway was reviewed by Weaver and Herrmann [17] and Hermann and Weaver [18] in biochemistry. It was seen in both plants and microorganisms. Shikimate was synthesized from the substrates erythrose 4-phosphate

*2.4.7 Isolation and characteristics of recombinant proteins*

are stored from experiments. It can be due to these reasons:

ultimately CO2. This method plays two fundamental roles:

1.Building blocks for anabolism*.*

*2.5.1.2 The pentose phosphate pathway*

ribulose5-phosphate,

*2.5.1.3 The shikimate pathway*

This pathway is divided into two phases:

1.No competing proteins with similar action.

**2.5 Other biosynthesis of phenolic compounds**

concentration [10, 11].

*2.5.1 Carbohydrate catabolism*

pathways etc.

*2.5.1.1 Glycolysis*

**228**

and phosphoenolpyruvate. By glycolysis and the pentose phosphate pathway, these two precursors are extracted respectively, and by the enzyme DAHP synthase, they are condensed to 3-deoxy-D-arabino-heptulosonate 7- phosphate. This steps end in the formation of 3-dehydroquinate by the enzyme 3- dehydroquinate synthase, 3-dehydroshikimate and 3- dehydroquinate dehydratase, and finally shikimate by the enzyme shikimate dehydrogenase. Shikimate was converted to shikimate 3-phosphate by shikimate kinase, then to 5-enolpyruvylshikimate 3-phosphate by 5-enolpyruvylshikimate 3-phosphate synthase. EPSP is then obtained to chorismate by chorismate synthase. Chorismate is bifurcate tryptophan on the one hand, and phenylalanine and tyrosine on the opposite hand for the biosynthesis of aromatic amino acids [8, 10–16].
