# US 4,396,477 A · Separation of proteins using electrodialysis-isoelectric focusing combination

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- Number: US 4,396,477 A
- Document ID: US4396477A
- Status: Granted
- Kind: A
- Application number: 06/278,267
- Filed: 1981-06-29
- Granted: 1983-08-02
- Earliest claimed: 1981-06-29
- Assignees: Ionics, Incorporated
- Inventors: Surendar M. Jain
- Web page: https://patentgrep.com/patent/US4396477A

## CPC

- B01D 61/44: Ion-selective electrodialysis
- B01D 57/02: by electrophoresis (treatment of water, waste water, sewage or sludge by electrophoresis C02F1/469; electrophoretic production of compounds or non-metals C25B7/00; investigating or analysing materials by using electrophoresis G01N27/26)
- G01N 27/44773: {Multi-stage electrophoresis, e.g. two-dimensional electrophoresis}
- G01N 27/44795: {Isoelectric focusing}
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A process and apparatus for treating a liquid protein mixture is disclosed in which the protein mixture is first determined by electrodialysis (ED) and then subjected to isoelectric focusing (IEF) to effect the separation of proteins based on differences in their isoelectric points (pI). This combination of ED-IEF results in an improved separation of the protein components of a mixture than without the ED step.

## Claims

### Claim 1

A process for the treatment of a liquid mixture of proteins comprising the steps of: first demineralizing said protein mixture by subjecting the same to electrodialysis at a temperature of between 0.degree.-40.degree. C. to effect a substantial reduction in the salt content of said mixture to a conductivity in the range between about 0.25-2.0 milli-Siemen/cm; removing from said demineralized mixture any turbidity present, and thereafter subjecting said resulting demineralized protein mixture to isoelectric focusing to effect therefrom a seperation and a simultaneous increase in the relative percentage of at least one of said proteins in at least one channel or separation path of said isoelectric focusing apparatus.

### Claim 2 (depends on 1)

The process of claim 1 where the isoelectric focusing process employs recirculation of said protein mixture through said focusing apparatus.

### Claim 3 (depends on 1)

The process of claim 1 whereby the isoelectric focusing is carried out with the use of carrier ampholytes.

### Claim 4 (depends on 1)

The process of claim 1 whereby the isoelectric focusing is carried out by forming a pH gradient by non-mobile charged or chargeable groups immobilized in a matrix along the separation path or channel.

### Claim 5 (depends on 1)

The process of claim 1 whereby the isoelectric focusing is carried out by forming a pH gradient by non-mobile charged or chargeable groups immobilized at least on the surface of the membranes forming the channels of the isoelectric focusing cell.