Immobilization of active protein by cross-linking to inactive protein

DETAILED DESCRIPTION The invention has two major inseparable aspects.
One concerns novel immobilized active protein, and the other concerns processes for producing the novel immobilized active protein.
The product, i.
e.
the immobilized protein, comprises compounds wherein active protein is chemically bound to inactive protein through bridges provided by a bi- or poly-functional cross-linking agent.
Although no carrier is required to produce the immobilized active protein in the form of a self-sustaining flexible sheet or film, the inactive protein is optionally employed in a suitable form to serve this purpose.
Alternatively, a separate, inert, non-proteinic carrier is used to impart form and additional strength to the product.
An open-cell foam or sponge form of the product is also contemplated.
Although the active protein is preferably an enzyme, its scope is virtually unrestricted.
It includes antigens, allergens, antibodies, hormones and proteinic parts of viruses or of cells.
It also includes, e.
g.
, pepsin, subtilisin, trypsin, chymotrypsin and papain, as well as active protein found in microbes.
Illustrative of the enzymes are: glucose-oxidase, carbonic anhydrase, proteolytic hydrolase, lypolytic hydrolase, amylolytic hydrolase, urease, asparaginase, uricase, peroxidase, catalase, phenylalanine-hydroxylase, galactose phosphate uridyl transferase, pronase, collagenase, keratinase, elastase, urate oxidase, tyrosine decarboxylase, hexokinase, phosphatase, L-amino-acid-oxidase, xanthine oxidase, decarboxylase, ribonuclease, .
alpha.
-anylase and .
beta.
-galactosidase.
The inactive protein is, e.
g.
, albumin, plasma protein, ovalbumin, fibrinogen, gelatin or hemoglobin, as well as inactive protein found in microbes.
Although other cross-linking agents are useful to produce one of the contemplated solid products, glutaraldehyde is the only cross-linking agent presently known to be effective for producing both self-supporting membranes or sheets and porous (freeze-dried) immobilized protein substances