Mass spectrometry methods for simultaneous detection of metabolic enzyme activity and metabolite levels

A method for detecting a metabolic disorder in an individual, comprising:

• (a) contacting a vessel containing one or more substrates in dried form with a sample from said individual, the sample containing
• (i) one or more metabolically indicative enzymes and
• (ii) one or more metabolic analytes,
• in aqueous solution;
• under conditions wherein at least one of said enzymes is capable of acting on a corresponding substrate to generate at least one product;
• (b) adding a reagent that inhibits the ability of said one or more enzymes to act on a corresponding substrate, wherein said one or more metabolic analytes and at least one product are soluble in said reagent;
• (c) determining the presence or amount of said one or more metabolic analytes and said at least one product in the resultant mixture using mass spectrometry,
• wherein a determined presence or amount of said one or more metabolic analytes and said at least one product correlates with presence or absence of said metabolic disorder.

A method for detecting a metabolic disorder in an individual, comprising:

• (a) contacting a sample comprising:
• (i) one or more metabolically indicative enzymes and
• (ii) one or more metabolic analytes,
• with one or more substrates for said one or more enzymes to produ e a reaction admixture, under conditions in which at least one of said enzymes is capable of acting on a corresponding substrate to generate at least one product;
• (b) contacting said reaction admixture with a reagent that inhibits the ability of said one or more enzymes to act on a corresponding substrate, wherein said one or more metabolic analytes and said at least one product are soluble in said reagent, to produce a test sample;
• (c) contacting said reaction admixture with one or more reference products and one or more reference analytes, and
• (d) determining the presence or amount of said one or more metabolic analytes and said at least one product contained in said test sample, with respect to said one or more reference products and one or more reference analytes, using mass spectrometry,
• wherein a determined presence or amount of said one or more metabolic analytes and said at least one product correlates with presence or absence of said metabolic disorder.

A method for detecting a metabolic disorder in an individual, comprising:

• (a) separating a sample into two sample portions, the sample comprising:
• (i) one or more metabolically indicative enzymes and
• (ii) one or more metabolic analytes;
• (b) contacting each sample portion with one or more substrates for said one or more enzymes to produce two reaction admixtures, under conditions in which at least one of said enzymes in each sample portion is capable of acting on a corresponding substrate to generate at least one product;
• (c) contacting each reaction admixture with a reagent that inhibits the ability of said one or more enzymes to act on a corresponding substrate, wherein said reagent can be the same or different for each reaction admixture, and wherein said one or more metabolic analytes and said at least one product are soluble in said reagent or reagents;
• to produce a test sample and
• (d) combining the two reaction admixtures to produce a test sample, and
• (e) determining the presence or amount of said one or more metabolic analytes and said at least one product contained in said test sample using mass spectrometry,
• wherein a determined presence or amount of said one or more metabolic analytes and said at least one product correlates with presence or absence of said metabolic disorder.

A method for detecting a metabolic disorder in an individual, comprising:

• (a) separating a sample into two sample portions, the sample comprising:
• (i) one or more metabolically indicative enzymes and
• (ii) one or more metabolic analytes;
• (b) contacting each sample portion with individual vessels, each vessel containing one or more substrates for said one or more enzymes in dried form,
• (c) contacting each vessel with a solution to produce two reaction admixtures, under conditions in which at least one of said enzymes in each sample portion is capable of acting on a corresponding substrate to generate at least one product;
• (d) contacting each reaction admixture with a reagent that inhibits the ability of said one or more enzymes to act on a corresponding substrate, wherein said reagent can be the same or different for each reaction admixture, and wherein said one or more metabolic analytes and said at least one product are soluble in said reagent or reagents;
• to produce a test sample and
• (e) combining the two reaction admixtures to produce a test sample, and
• (f) determining the presence or amount of said one or more metabolic analytes and said at least one product contained in said test sample using mass spectrometry,
• wherein a determined presence or amount of said one or more metabolic analytes and said at least one product correlates with presence or absence of said metabolic disorder.

A method for detecting a metabolic disorder in an individual, comprising:

• (a) contacting a vessel containing one or more substrates in dried form with a sample from said individual, the sample containing
• (i) one or more metabolically indicative enzymes and
• (ii) one or more metabolic analytes,
• (b) contacting said vessel with a solution to generate conditions wherein at least one of said enzymes is capable of acting on a corresponding substrate to generate at least one product;
• (c) adding a reagent that inhibits the ability of said one or more enzymes to act on a corresponding substrate, wherein said one or more metabolic analytes and at least one product are soluble in said reagent;
• (d) determining the presence or amount of said one or more metabolic analytes and said at least one product in the resultant mixture using mass spectrometry,
• wherein a determined presence or amount of said one or more metabolic analytes and said at least one product correlates with presence or absence of said metabolic disorder.