Claims for Patent: 5,310,670

Summary for Patent: 5,310,670

Title:	Method for the purification of Erwinia L-asparaginase
Abstract:	A process is provided for the purification of L-asparaginase by contacting a crude extract of L-asparaginase with a solid medium having cation exchange groups so as to adsorb L-asparaginase on the support and eluting adsorbed L-asparaginase from the support. The cation exchange groups comprise sulphonate groups and the elution step is carried out at a pH which is higher than the pH used in the contacting step.
Inventor(s):	Goward; Christopher R. (London, GB2)
Assignee:	Public Health Laboratory Service Board (London, GB2)
Application Number:	07/867,105
Patent Claims:	1. A process for producing purified asparaginase which comprises the steps of (i) extracting L-asparaginase from disrupted cells at a pH of from 11.3 to 11.5, (ii) adjusting the pH to within the range 6.3 to 6.7, (iii) separating supernatant from precipitated impurities, (iv) subjecting supernatant from step (iii) to adsorption on a solid medium, having cation exchange groups so as to adsorb L-asparaginase on the solid medium wherein the cation exchange groups comprise sulphonate groups, and (v) eluting adsorbed L-asparaginase, and wherein the contacting of the supernatant with the solid medium in step (iv) is effected at a pH of from 4.0 to 5.5, and wherein the eluting of adsorbed L-asparaginase in step (v) is effected at a pH of from 6.0 to 7.5. 2. A process according to claim 1 wherein the sulphonate groups form part of groups of the formula --(CH.sub.2).sub.n SO3.sup.- wherein n=1 to 3. 3. A process according to claim 1 wherein the support is derived from agarose. 4. A process according to claim 1 wherein the pH in step (v) is within the range 6.6 to 7.0. 5. A process according to claim 1 wherein the L-asparaginase subjected to purification has substantially the amino acid sequence of E chrysanthemi L-asparaginase. 6. A process according to claim 1 wherein the L-asparaginase subjected to purification has at least 90% sequence homology with that amino acid sequence depicted in FIG. 1. 7. A process according to claim 1 wherein the L-asparaginase subjected to purification has at least 95% sequence homology with that amino acid sequence depicted in FIG. 1. 8. A process according to claim 1 wherein the L-asparaginase subjected to purification has at least 99% sequence homology with that amino acid sequence depicted in FIG. 1. 9. A process according to claim 1 wherein the crude extract is produced by culturing a transformed microorganism containing a recombinant plasmid having a DNA insert coding for said L-asparaginase. 10. A process according to claim 1 wherein the crude extract is obtained by culturing E chrysanthemi.

Details for Patent 5,310,670

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Recordati Rare Diseases, Inc.	ELSPAR	asparaginase	For Injection	101063	01/10/1978		2011-05-10