Using Heat-Resistant Enzymes to Read DNA Sequences Faster
This patent describes using a heat-stable enzyme from a bacterium that lives in hot springs to make the process of reading DNA code much more reliable and efficient.
Original patent title: “Methods for dna sequencing with thermus aquaticus dna polymerase”
This patent describes using a heat-stable enzyme from a bacterium that lives in hot springs to make the process of reading DNA code much more reliable and efficient. Granted to Cetus Corp in 1991 with 33 claims and 146 forward citations.
Key facts
Coverage
What does this patent actually cover?
The patent improves the Sanger sequencing method, which reads DNA by stopping the building process at specific points using special molecules called dideoxynucleotides. Previously, researchers used enzymes that broke down at high temperatures, causing errors and incomplete readings. By using DNA polymerase from Thermus aquaticus (Taq), an organism that thrives in boiling water, the reaction can be performed at higher temperatures. This helps the DNA strands stay open and prevents them from tangling, leading to much clearer and more accurate results.
The gap
What does this patent NOT cover?
- Does not cover the fundamental Sanger sequencing method itself, only the use of Taq polymerase within it.
- Does not cover the discovery of the Thermus aquaticus organism.
- Does not cover sequencing methods that do not use dideoxynucleotide chain termination.
- Does not cover the use of DNA polymerases derived from organisms other than Thermus aquaticus.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The inventors realized that the heat-stability of the Taq enzyme, originally prized for PCR, was the perfect solution to the 'secondary structure' problem in DNA sequencing, where DNA strands fold onto themselves and block the reading process.
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Standard Sanger sequencing protocols used in clinical diagnostics
Automated capillary electrophoresis DNA sequencers
Molecular biology research kits for gene mapping
Why it matters
The bigger picture
This innovation was a critical step in the automation of DNA sequencing, which eventually enabled the Human Genome Project. By making the sequencing reaction robust enough to withstand high temperatures, it allowed scientists to read longer and more complex stretches of DNA without the frequent failures that plagued earlier methods.
Filed
September 23, 1988
Granted
December 24, 1991
Market context
Who's building on this
Companies in this space
Companies like Thermo Fisher Scientific and Illumina have built massive businesses on the foundation of high-fidelity, heat-stable enzymes for genomic analysis. The techniques pioneered here are now standard in every molecular biology lab globally.
Market impact
This patent helped standardize the workflow for DNA sequencing, transitioning it from a finicky, manual laboratory craft to a reliable, scalable industrial process. It provided the technical foundation for the massive growth of the genomics industry throughout the 1990s and 2000s.
Claim 1 — Plain English
What this patent covers
The patent improves the Sanger sequencing method, which reads DNA by stopping the building process at specific points using special molecules called dideoxynucleotides. Previously, researchers used enzymes that broke down at high temperatures, causing errors and incomplete readings. By using DNA polymerase from Thermus aquaticus (Taq), an organism that thrives in boiling water, the reaction can be performed at higher temperatures. This helps the DNA strands stay open and prevents them from tangling, leading to much clearer and more accurate results.
The clever bit
The inventors realized that the heat-stability of the Taq enzyme, originally prized for PCR, was the perfect solution to the 'secondary structure' problem in DNA sequencing, where DNA strands fold onto themselves and block the reading process.
What it does not cover
- Does not cover the fundamental Sanger sequencing method itself, only the use of Taq polymerase within it.
- Does not cover the discovery of the Thermus aquaticus organism.
- Does not cover sequencing methods that do not use dideoxynucleotide chain termination.
- Does not cover the use of DNA polymerases derived from organisms other than Thermus aquaticus.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
PatentBrief Score
Impact Score
Strong
Citation count
40/40
Highly cited
Claim breadth
20/20
Very broad protection
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$216K – $691K
Midpoint $432K · expired or expiring · industry ×3.0
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
The original legal language
Original claims
33 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Gelfand, D. H., Myambo, K. B., Innis, M. A., & Brow, M. A. D. (1991). Using Heat-Resistant Enzymes to Read DNA Sequences Faster (U.S. Patent No. 5,075,216). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/5075216/modified-taq-polymerase
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does Using Heat-Resistant Enzymes to Read DNA Sequences Faster cover?
This patent describes using a heat-stable enzyme from a bacterium that lives in hot springs to make the process of reading DNA code much more reliable and efficient.
Who owns patent US 5075216?
Cetus Corp owns this patent, granted in 1991.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 5075216 cited by?
This patent has been cited by 146 later patents that build on its ideas.
What problem does this patent solve?
This innovation was a critical step in the automation of DNA sequencing, which eventually enabled the Human Genome Project. By making the sequencing reaction robust enough to withstand high temperatures, it allowed scientists to read longer and more complex stretches of DNA without the frequent failures that plagued earlier methods.
What does this patent NOT cover?
Does not cover the fundamental Sanger sequencing method itself, only the use of Taq polymerase within it.
Same assignee
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