Methods of isolating and detecting metal ions from proteins

• US 10,451,599 B2
• Filed: 09/02/2016
• Issued: 10/22/2019
• Est. Priority Date: 09/02/2016
• Status: Active Grant

• Current Assignee: Zepto Life Technology Incorporated
• Original Assignee: Zepto Life Technology, LLC
• Inventors: Sinha, Joy, Aguirre, Gerson
• Primary Examiner(s): Underdahl, Thane
• Application Number:
  US15/255,756
• Publication Number:
  US 20180067094A1
• Time in Patent Office: 1,145 Days
• Field of Search: None
• CPC Class Codes: A61K 38/482 Serine endopeptidases (3.4.21)
• CPC Class Codes: C12N 9/50 Proteinases , e.g. Endopeptidases (3.4.21-3.4.25)
• CPC Class Codes: C12N 9/6408 Serine endopeptidases (3.4.21)
• CPC Class Codes: C12N 9/6424 Serine endopeptidases (3.4.21)
• CPC Class Codes: C12Y 304/21 Serine endopeptidases (3.4.21)
• CPC Class Codes: G01N 33/04 Dairy products
• CPC Class Codes: G01N 33/20 Metals
• CPC Class Codes: G01N 33/84 involving inorganic compounds or pH

Abstract

A method of detecting a metal ion in a protein-containing sample includes adding a protein degrading enzyme to the protein-containing sample to form an enzyme degradation product, adding an acid to the enzyme degradation product to provide a mixture, filtering the mixture to provide a supernatant, extracting the supernatant with an organic solvent to remove organic solvent soluble byproducts to provide a washed aqueous layer, and detecting the metal ion in the washed aqueous layer. The method is amenable to the detection of heavy metal ions in complex products such as milk. A kit includes reagents for performing the method.

Claims

1. A kit comprising:

a container for holding a protein-containing sample;

proteinase K;

concentrated nitric acid;

chloroform;

a handheld device for detecting metal ions, the handheld device employing detection based on giant magnetoresistance; and

instructions for performing the isolation of metal ions from the protein-containing sample.

2. The kit of claim 1, wherein the kit is a small scale kit for performing the isolation of metal ions in the field.

3. The kit of claim 1, further comprising other protein denaturing agents.

4. The kit of claim 3, wherein the further protein denaturing agents comprise at least one selected from the group consisting of sodium dodecyl sulfate (SDS), urea, ethylenediamine tetraacetic acid, trypsin, and chymotrypsin.