文档介绍：Preface
The use of enzymes – employed either as isolated enzymes, crude protein
extracts or whole cells – for the transformation of non--
pounds is not an invention of the twentieth century: they have been used for
more than one hundred ,the object of most of the early research
was totally different from that of the present day. Whereas the elucidation of
biochemical pathways and enzyme mechanisms was the main driving force for
the early studies, in contrast it was mainly during the 1980s that the enormous
potential of applying natural catalysts to transform non--
pounds was recognized. This trend was particularly well enhanced by the
mendation of the FDA-guidelines (1992) with respect to the use of chiral
bioactive agents in enantiopure form.
During the last two decades, it has been shown that the substrate tolerance
of numerous biocatalysts is often much wider than previously believed. Of
course, there are many enzymes which are very strictly bound to their natural
substrate(s). They play an important role in metabolism and they are general-
ly not applicable for biotransformations. On the other hand, an impressive
number of biocatalysts have been shown to possess a wide substrate tolerance
by keeping their exquisite catalytic properties with respect to chemo-, regio-
and, most important, enantio-selectivity. This made them into the key tools
for biotransformations. As a result of this extensive research during the last
two decades, biocatalysts have captured an important place in contemporary
organic synthesis, which is reflected by the fact that ~ 8% of all papers on
anic chemistry contained elements of biotransformations as
early as in 1991 with an ever-increasing proportion. It is now generally ac-
cepted, that biochemical methods represent a powerful synthetic tool -
plement other methodologies in modern anic chemistry.
Whereas several areas of biocatalysis – in particular the use of easy-to-use
hydrolases, such as