Provided are a recombinant protein, a gene encoding the recombinant protein, a recombinant microorganism including the gene, and a method of degrading a macromolecular substance using the recombinant microorganism or the recombinant protein.

The present invention is directed to provide novel methods of producing hydroxystilbene. According to the present invention, as a method of producing a compound having the general formula (II),

##STR00001##

in which R.sup.1 to R.sup.3 are each H, OH or OR; R is independently selected from a C1-6 alkyl group and a glycosyl group; and one of R.sup.4 and R.sup.5 is H and the other is OH, 4-hydroxyphenylacetate 3-hydroxylase (HPAH) is administered to a compound having the general formula (I),

##STR00002##

in which R.sup.1 to R.sup.3 are each H, OH or OR; and R is independently selected from a C1-6 alkyl group and a glycosyl group.

Compounds and methods are providing involving RebH variants with improved properties. directed evolution based on random mutagenesis was employed to generate a series of RebH variants. RebH variants with improved thermostability and increased activity at elevated temperatures were generated.