Chemistry Reference
In-Depth Information
Subsequent mutagenesis at this region was performed for general understanding of the rule
in order to create mutants with least selectivity for hydrolysis so that the industrial production
of trehalose can be greatly improved. These mutants, including F405M, F405S and F405W,
showed that the decrease of hydrophobic interactions between the enzyme and substrate
indeed, generally, led to the better selectivity towards transglycosylation versus hydrolysis.
However, with mutant F405Y the highest yield of trehalose was obtained, indicating that
it is a potentially better suited biocatalyst. However, mutants designed for decreasing the
hydrophobic interactions between the enzyme and substrate at the
1 region did not give
a positive mutant, indicating the complexity of forces and interactions that exist within the
microenvironment of an enzyme's three-dimensional structure.
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2.3.5 Safety concerns
It has been demonstrated that protein engineering is a powerful tool for improving an
enzyme's physiochemical characteristics, such as catalytic properties and selectivity, to
make the enzyme better suited for its working conditions. Enzymes used as processing aids,
such as those used for bioconversions, are usually separated from products after the reaction.
These bioconversion products are further purified, and in such cases the safety concern of
engineered enzymes is less substantial. However, where the enzyme is added to food materials
and remains in the food after processing, even if denatured at the end, safety concern is the
main issue for consumer judgement. Enzymes modified by protein engineering usually have
high homology with the wild type and only subtle changes in conformation and structures are
made. Hence, it is arguable that these enzymes will pose dramatic safety threats. However,
some changes might influence the digestibility of an enzyme and the resulting peptides might
impose adverse health effects such as causing allergenic reactions. Therefore, it should be
kept in mind that proper safety evaluations should always be performed before putting a
modified enzyme into the market. Engineered proteins or enzymes are nevertheless new
materials and should be released only after stringent safety assessments.
2.4
REGULATIONS
Despite the fact that transgenic organisms generated by genetic engineering and protein
engineering are still bashed in most places of the world, products originated from using
these technologies are penetrating our lives. These products are under strict regulations to
guarantee the well-being of our society. Countries such as Japan and those of the European
Union (EU) have set strict rules for regulating products that originate from the application
of these modern biotechnologies. The regulations are based on environmental concerns, as
well as human and animal health.
In Japan, the Food Safety Commission was founded in 2003; one of its responsibilities
is to evaluate the safety of genetically modified food or feed. The standards and guidelines
that have been established since then can be found on the official home page of Food Safety
Commission (http://www.fsc.go.jp/senmon/idensi/index.html):
The safety assessment of genetically modified foods (seed plants).
Guidelines for safety assessment of recombinant crossbred plants.
Standard
for
safety
assessment
of
food
additives
produced
by
recombinant
microorganisms.
