United States: Federal Circuit Holds Patentee To Functional Claim Language

In Bayer Cropscience AG v. Dow AgroSciences LLC, the Federal Circuit upheld the district court's claim construction that interpreted "2,4-D monooxygenase" in accordance with its  established scientific meaning, even though the exemplified embodiment was shown not to be a "monooxygenase." This case illustrates the risks of functional claim language, particularly if the recited function is proven to be inapplicable, but also if the specification does not provide adequate written description for the breadth of embodiments encompassed by the functional language.

The Patent At Issue 

The patent at issue was Bayer's U.S. Patent 6,153,401, which relates to constructs and methods for "genetically modifying plants in order to confer resistance to a commonly used herbicide called 2,4-dichlorophenoxyacetic acid, or '2,4-D' for short." The methods involve genetically modifying plants to express an enzyme that catalyzes a reaction that breaks the herbicide down "into something harmless to plants." Claim 1 recites:

A recombinant gene, comprising a DNA sequence encoding a polypeptide having the biological activity of 2,4-D monooxygenase which is capable of being expressed in a plant, operably linked to a heterologous promoter capable of promoting the expression in a plant of a structural gene operably linked thereto.

Dependent claim 4 recites embodiments of claim 1 "wherein the DNA sequence is the structural gene sequence of FIG. 10."

The "Monooxygenase" Issue

As summarized by the Federal Circuit, at the time the patent was filed it was known that "certain bacteria found in soil could grow on 2,4-D," and that "those bacteria first convert 2,4-D into a substance called 2,4-dichlorophenol, or '2,4-DCP,' which the bacteria ... use as a 'source[] of carbon and energy.'" Thus, scientists were trying to identify the genes that encoded enzymes that catalyzed that reaction. According to the Federal Circuit decision, "[t]he inventors of the '401 patent were the first 'to isolate, to clone, and to characterize' a gene that had that property, a gene from the soil bacterium strain Alcaligenes eutrophus JMP134." The nucleotide sequence of that gene is set forth in Figure 10 of the patent, and is the only gene identified in the 'patent.

According to the Federal Circuit, although the inventors had identified an enzyme of interest, "they did not fully understand the enzymatic reaction that they were studying." For example, while "the reaction requires the presence of the oxygen molecule, O2, ... the inventors did not know where one of the two oxygen atoms wound up." At the time the patent was filed, they and others in "the scientific community" believed that it "was incorporated into water." In accordance with this understanding, the patent refers to the enzymes of interest as "monooxygenases." Importantly, the record "established beyond dispute"  that the term "monooxygenases" refers to "enzymes catalyzing a reaction in which one oxygen atom ends up in water and the second is incorporated into a product other than water."

While the '401 patent still was pending, it was determined that the enzyme it described was not a "monooxygenase" because the second oxygen atom does not end up in water, but rather is "incorporated into products other than water."   As such, the enzyme is properly characterized as a "dioxygenase."

[D]espite the announcement of this discovery in the very title of the article, and Bayer's knowledge of the article, Bayer did not alter the claims of its application—which did not mature into a patent until seven years after the 1993 discovery.

The Accused Products

The accused products relate to Dow AgroSciences' genetically modified seeds that are resistant to 2,4-D and other herbicides. Dow's genes are dioxygenases that catalyze a reaction in which 2,4-D converts to 2,4-DCP.

The District Court Decision 

Bayer asserted that its claims encompass "any enzyme that triggers cleaving of the side chain of 2,4-D to produce 2,4-DCP, even if it is a dioxygenase and even if it does not share other biological activities of the particular enzyme whose gene Bayer sequenced." The district court rejected Bayer's arguments, and construed the "monooxygenase" claim language in accordance with its ordinary eaning, i.e., as reciting enzymes that catalyze reactions in which one oxygen atom ends up in a water molecule.  Since Dow's enzymes are dioxygenases, Dow does not infringe under that claim construction.

The Federal Circuit Decision

The Federal Circuit conducted a two-part analysis of Bayer's claim construction arguments.

First, the court found that the intrinsic record did not support the broad claim construction.

The conclusion we draw is that there is no clear message that the patent gives Bayer's broad meaning to "2,4-D monooxygenase" in place of the term's accepted scientific meaning, which describes a particular mechanism of action. ....

In short, as the district court explained, the claim language has a strong accepted scientific meaning. Bayer's alternative construction strips the monooxygenase half of the claim phrase of its accepted descriptive meaning and then asserts a specification "definition" of the biological-activity half. We do not find enough in the specification or prosecution history to justify those steps.

Second, the court noted if the claims were construed as broadly as Bayer urged, they likely would be invalid under 35 USC § 112.

Bayer's proposed construction broadly covers a class of enzymes defined by their function of causing cleaving of the side chain of 2,4-D, while its written description structurally identifies just one gene sequence and the enzyme it encodes. We have not articulated a comprehensive and precise formulation for identifying when such a combination runs afoul of Section 112(a)'s written description requirement; indeed, we have counseled against "bright-line rules" in this area. ... But we have indicated the primacy of structural identification for inventions in certain areas like the one at issue here, and when we have adverted to the possibility of other means of identification, we have focused on whether such alternative means sufficiently correlate with structure....

The coverage of claim 1 that Bayer proposes would leave the '401 patent far from providing even an indirect structural identification of all that would be within the claim's scope. The enzymatic function—under Bayer's construction, causing the cleaving of the side chain of 2,4-D—would be broad, yet the patent provides the DNA sequence (and hence amino-acid sequence) of just one embodiment. As the district court explained, ... neither the patent nor the knowledge in the art showed that what Bayer offered in place of a description of the shared structure—the growth test—correlated closely with an enzyme's structure. The patent provided what was "[a]t best . . . a roadmap [that would] 'leav[e] it to the . . . industry to complete [the] unfinished invention.'"

Thus, the Federal Circuit affirmed the district court's claim construction and the summary judgment of non-infringement.

Caveat Patentee

The Federal Circuit noted that the district court decision referenced precedential "decisions about the potentially unwelcome consequences of a patentee's chosen claim language." Further, the Federal Circuit remarked several times that the patentee was aware of the discovery that its enzyme was not a monooxygenase, but "did not change its claim language." What is not clear from the Federal Circuit decision is who at Bayer was aware of the discovery and whether they were actively involved in prosecuting the patents.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

In association with
Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement

Mondaq.com (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of www.mondaq.com

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about Mondaq.com’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to unsubscribe@mondaq.com with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


From time to time Mondaq may send you emails promoting Mondaq services including new services. You may opt out of receiving such emails by clicking below.

*** If you do not wish to receive any future announcements of services offered by Mondaq you may opt out by clicking here .


This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to webmaster@mondaq.com.

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to EditorialAdvisor@mondaq.com.

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at enquiries@mondaq.com.

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at problems@mondaq.com and we will use commercially reasonable efforts to determine and correct the problem promptly.