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In this article we will discuss about the therapeutic products that are easily available in markets.
1. Avidin:
Avidin is a glycoprotein with four subunits found in avian, reptilian and amphibian egg white. It is used as diagnostic reagent. Each identical subunit is made up of 128 amino acids. Presently available avidin product from chicken egg in expensive production of avidin (chicken egg white) in transgenic corn using an avidin gene whose sequence had been optimized for expression in corn.
The avidin produced in plant had properties almost identical to those of avidin from chicken egg white. Both the corn derived and the chicken egg derived avidin was glycosylated. Corn derived avidin expression levels over 20% of total soluble protein have been observed.
2. Trypsin:
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Recently, trypsin has been produced in maize plant. It has a significant market potential. Trypsin is a protease used commercially including of some biopharmaceuticals. The more aggressive proteolytic trypsin enzyme has beer produced at commercial viable level in maize by expressing the enzyme in an inactive zymogen form.
Although the zymogen gene was introduced in the plants, the active enzyme was recovered in extracts from maize seeds. Almost all of the trypsinogen was converted to trypsin in the seed. The product names Trypzean is the first large scale protein product from transgenic plant technology.
3. Glucoronidase (GUS):
It is widely used as marker in transgenic plant research. It was first produced commercially in transgenic corn. After analysis of plant derived GUS enzyme, it was shown that their Km values were nearly identical (0.20 Vs. 0.21) and their Vmax values for its substrate MuG (4-methyl umbelliferyl-β-D-glucoronide) were also quite similar 2.9 × 105 nM/λ for corn derived Vs. 2.2 × 105 nm/h for E. coli derived. Corn derived GUS has been marketed by Sigma Aldrich.
4. Aprotinin:
It is a protein inhibits serine proteases (trypsin, chymotrypsin etc.). This protein is used to reduce systemic inflammatory response during heart bypass surgery (cardiopulmonary), currently; aprotinin is extracted from bovine lungs.
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However, due to high market price, a non-animal derived, lower cost aprotinin production was targeted. Recombinant bovine aprotinin from transgenic corn was successfully produced and its expression level reached up to 0.068%.
5. Collagen:
It is a structural protein currently derived from connective tissues of animals. Vast quantities of collagen are consumed worldwide each year in the form of gelatin. It is also used as biomaterial in cosmetic and pharmaceutical industry. It is employed for various reasons like tissue engineering, drug delivery, bone graft etc.
The first collagen product was produced in transgenic tobacco. Researchers inserted the fibrillar collagen cDNA 1α3 and α22, which together code for the complete human proα1(I) collagen chain, into tobacco. The resultant protein was organised into triple helix, and currently several companies have reported interest in bringing human collagen to market.
6. Human Lactoferrin:
Human lactoferrin is a natural defense iron-binding milk protein. It is antibacterial, antifungal and also has anti-inflammatory properties. Presently, it is obtained from cow’s milk at very low level. Lactoferrin product was reported in tobacco suspension culture. California based company like Ventria attempted to commercialize lactoferrin from rice and maize seeds.
