Technicon Instruments Corporation

Owens-illinois, Inc.

Owens-illinois Glass Container Inc.

Melvin H Keyes

Garry L Moore

Raymond C Barabino

Don N Gray

Saraswathi Vasan

A naturally occurring protein is chemically modified to provide the protein with activity of a selected enzyme. The protein does not contain activity of the selected enzyme before modification. Modification is carried out by partially denaturing the protein, contacting the partially denatured protein with an enzyme inhibitor of the selected enzyme, crosslinking the protein in the presence of the inhibitor and recovering a modified protein having activity of the selected enzyme.

Protein modification to provide enzyme activity

A naturally occuring protein is chemically modified to provide the protein with activity of a selected enzyme. The protein does not contain activity of the selected enzyme before modification. Modification is preferably carried out by partially denaturing the protein in the presence of an inhibitor for the selected enzyme to form a partially denatured protein-enzyme inhibitor complex, adsorbing the complex to a solid support and crosslinking the adsorbed complex to form an immobilized modified protein having activity of the selected enzyme. Alternatively, the protein may be adsorbed onto the support, partially denatured and crosslinked in the presence of the inhibitor or the protein may be partially denatured, adsorbed on the support and crosslinked in the presence the inhibitor. In another embodiment, the protein has at least three disulphide groups. This protein is contacted with a disulphide bridge reducting agent in the presence of the inhibitor to produce a partially denatured protein-inhibitor complex, the complex is adsorbed onto a support and the adsorbed complex is contacted with a sulfhydryl oxidizing agent to form disulphide bonds in the protein to produce an immobilized modified protein having enzyme activity.

A naturally occurring protein is chemically modified to provide the protein with activity of a selected enzyme. The protein does not contain activity of the selected enzyme before modification. Modification is carried out by partially denaturing the protein, contacting the partially denatured protein with an immobilized enzyme inhibitor of the selected enzyme, crosslinking the protein in the presence of the inhibitor and recovering a modified protein having activity of the selected enzyme.

A naturally occurring protein is chemically modified to provide the protein with activity of a selected enzyme. The protein does not contain activity of the selected enzyme before modification. Modification is carried out by grossly denaturing the protein, partially renaturing the protein to form a partially denatured protein, contacting the partially denatured protein with an enzyme inhibitor of the selected enzyme, crosslinking the protein in the presence of the inhibitor and recovering a modified protein having activity of the selected enzyme.

A process is disclosed for chemically modifying naturally occurring proteins to produce enzyme-like modified proteins. The process comprises partially denaturing a cofactor containing holoprotein by removal of the cofactor to produce a partially denatured cofactorless or so-called apoprotein. The partially denatured protein is contacted with an inhibitor of a selected model enzyme and cross-linked. The resultant protein product is an enzyme-like modified protein having the catalytic characteristics of the model enzyme whose inhibitor is contacted with the partially denatured apoprotein.

Process for the production of modified proteins and product thereof

This invention relates to a method and apparatus for the rapid quantitative determination of an antigen contained in aqueous biochemical samples, for example, blood. The method comprises a series of sequentially arranged stages through which a buffered stream flows. The sample, containing an unknown concentration of the antigen, is injected into the buffered flowing stream and contacts various reagents in the sequential series of stages. An initial solubilization stage comprises an immobilized antibody on a substrate which antibody is specific to the antigen in the sample. The immobilized antibody has been reacted previously to saturation with an enzyme-antigen complex, the antigen of the complex being the same as the antigen in the sample, and the complex is reversably bound to the immobilized antibody. The antigen in the sample and buffered stream flow through the solubilization stage and a competitive equilibrium reaction takes place between the complex bound to the antibody and the antigen in the sample, resulting in the release of a quantity of the enzyme-antigen complex into the flowing stream. The complex and the stream pass into a conversion stage wherein the complex reacts with an immobilized substrate, such as starch, to produce a measurable product which is a quantitative index of the complex released in the solubilization stage. The measurable product and the stream flow to a detection stage wherein the product is reacted, quantitatively measured and related to the concentration of the antigen in the original sample.

Enzyme immunoassays using immobilized reagents in a flowing stream

A method for the quantitative determination of sugars in a fluid sample. The sugar sample, which may contain free glucose, is passed through a scavenger stage where substantially all of the glucose is removed, so that it does not interfere with the determination. The glucose-free sample is then passed through an immobilized glucose generating stage to produce glucose in molar proportion to the total initial concentration of the sugars present. The generated glucose is passed through an immobilized hydrogen peroxide generating stage to form gluconic acid and hydrogen peroxide. The generated hydrogen peroxide is detected in suitable detection means, typically a polarographic cell. Total free glucose is determined by measuring the total sugars in the sample by bypassing the scavenger stage, determining total sugar, then determining the glucose in the sample without bypassing the scavenger and measuring free glucose as the difference.

Apparatus for the quantitative determination of saccharides

A method for detecting the presence and quantitatively determining the amount of ionic or nonionic surfactants on a surface, particularly for the rapid determination of the surfactants on glass surfaces. The method comprises the use of an enzyme-substrate combination, including an enzyme which binds the ionic or nonionic surfactant on the surface, but is not deactivated, or inhibited, by the nonionic surfactant's binding. An indicator molecule is also present which is responsive to the product of the enzyme-substrate reaction. In operation, an aqueous solution of the enzyme and indicator is applied to the surface to be tested and sufficient time is allowed for any surfactant to dissolve and bind the enzyme. A solution of a standard ionic surfactant is then added which will bind and deactivate the enzyme if the enzyme has not been bound by any nonionic surfactant present. Finally, a solution of the enzyme substrate is added. Any color change in the test solution as a function of time, indicates the presence and concentration of the nonionic surfactant. To test for ionic surfactant, the step of addition of ionic surfactant may be omitted and the color change, if any, upon substrate addition is followed as a function of time.

Enzymatic method for determining surfactants on surfaces

A carbohydrate substrate such as starch for a carbohydrate hydrolyzing enzyme is immobilized on a solid inorganic porous support to form a stable substrate-support composite useful in affinity chromatography and in methods where a precise amount of substrate is needed to perform an enzyme-substrate reaction to quantify the enzyme. The substrate may be activated with an agent such as cyanogen bromide or imidazole prior to deposition on the support so that it may be effectively modified while on the support. After deposition, the substrate is modified by reaction with an epoxyhalogen, aliphatic dihalide or aliphatic diamine to aid in holding it on the support. In an alternative embodiment, the carbohydrate, prior to deposition and modification on the support, is hydrolyzed with an enzyme, preferably dextranase.

Immobilization of an enzyme substrate

A method of producing an immobilized protein composite, i.e. enzymes such as glucose oxidase, on an alumina support, comprising modifying some of the free functional groups of the protein such as amino groups, by reaction with an acid or anhydride, depositing the modified protein on a porous inorganic support at controlled pH and temperature, and cross-linking remaining free functional groups of the protein with adjacent deposited protein functional groups to form interprotein peptide bonds. The resultant composite has long-term continuous use.

Immobilization of proteins on inorganic supports

A method for producing an immobilized protein composite, particularly using enzyme and non-enzyme proteins, comprising selecting at least a first protein which is rich in cysteine and/or cystine amino acid residues, and a second protein which is poor in cysteine and/or cystine amino acid residues. These two proteins are deposited on an inorganic support and maintained at a pH and temperature for sufficient time to facilitate the copolymerization of the two proteins.

Copolymerization of proteins on an inorganic support

A method of economically producing a relatively rapidly soluble machine handleable particulate composite material from a material of relatively low solubility comprising pulverizing a material of low solubility, selecting a first appropriate size fraction from the pulverized material and mixing the selected fraction with a predetermined proportion of water to obtain a composite. The composite is dried at a predetermined temperature for a specified time. The dried composite is pulverized and a second selected appropriate size fraction is obtained. The second size fraction possesses increased solution solubility and machine handleability properties over the starting relatively low solubility material.

Method of preparing a rapidly soluble and machine handleable particulate

This invention relates to a method for purifying a carbohydrate containing enzyme which is a desired enzyme preferred to be separated from a mixture. The method comprises the steps of mixing a solution containing the carbohydrate containing enzyme with a carbohydrate modifying reagent. The carbohydrate modifying reagent reacts with the carbohydrate attached to the enzyme, thereby modifying its chemical structure. The modified enzyme is then separated from the other undesirable enzymes or proteins in the mixture by a suitable chemical separation method, for example, gel filtration chromatography. The method was used in the separation of glucose oxidase from catalase, a separation which by previous methods was very inefficient.

Process for the purification of carbohydrate containing enzymes

This invention relates to a method and apparatus for rapid quantitative determination of .alpha.-amylase in aqueous samples such as blood serum, etc. The method comprises a flow-through of the sample through various immobilized reagents contained in sequential stages. A scavenger stage initially removes glucose originally present in the sample and comprises immobilized glucose oxidase and catalase. The glucose-free sample flows through an immobilized starch stage substrate preferably containing a high percentage of amylose to quantitatively react with the .alpha.-amylase in the sample and produce oligosaccharides. The sample with the oligosaccharides flows through a glucose-generating stage containing immobilized glucoamylase which converts the oligosaccharides to glucose. The glucose-containing sample enters a detection stage wherein the glucose is converted to H.sub.2 O.sub.2 by flowing through immobilized glucose oxidase, and the H.sub.2 O.sub.2 produced is quantitatively detected in detection means such as a polarographic cell. The immobilized reagents are preferably contained in an apparatus which comprises at least one column in combination with the detection means and a readout means.

Growing community of inventors

Sylvania, OH, United States of America

Melvin H Keyes