what is semi-senthetic enzyme.s?

Answer 1

You mean semi-synthetic enzymes.

Enzymes are catalytic proteins. Thus they are produced by cells and are composed of the 20 naturally occuring L-amino acids.
If we purify an enzyme from an organism we speak about an isolated/purified enzyme and if we synthesize chemically the enzyme starting from amino-acids we are speaking about synthetic enzymes. Up to now usually only small peptides are synthesized from scratch.

However you can purify an enzyme produced by a microorganism and then chemically modify it in a way that changes completely its activity and usually that it is impossible to happen inside a living cell. Such an enzyme is considered to be semi-synthetic

For example Emil Thomas Kaiser converted a hydrolytic enzyme into one for oxidation-reduction by attaching a flavin coenzyme at the active site of a peptidase, papain (http://www.nap.edu/readingroom/books/biomems/ekaiser.html)

See also http://www.protein.ethz.ch/enzyme.html