# US 5,707,839 A · Genes encoding branched-chain alpha-ketoacid dehydrogenase complex from streptomyces avermitilis

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- Number: US 5,707,839 A
- Document ID: US5707839A
- Status: Granted
- Kind: A
- Application number: 08/470,892
- Filed: 1995-06-06
- Granted: 1998-01-13
- Earliest claimed: 1993-12-16
- Assignees: Pfizer Inc.
- Inventors: Claudio D. Denoya; Kim J. Stutzman-Engwall
- Web page: https://patentgrep.com/patent/US5707839A

## CPC

- C12N 9/0008: {acting on the aldehyde or oxo group of donors (1.2)}
- C12N 15/52: Genes encoding for enzymes or proenzymes
- C12P 19/62: the hetero ring having eight or more ring members and only oxygen as ring hetero atoms, e.g. erythromycin, spiramycin, nystatin
- C12Y 102/04004: 3-Methyl-2-oxobutanoate dehydrogenase (2-methylpropanoyl-transferring) (1.2.4.4), i.e. branched-chain-alpha-ketoacid dehydrogenase
- C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00)
- C12P: FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE {(brewing of beer C12C; producing vinegar C12J; producing specific peptides or proteins C07K; producing enzymes C12N9/00; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; measuring or testing processes involving enzymes or microorganisms C12Q; measuring or testing processes involving nucleic acid amplification reactions C12Q1/6844; fermentation processes to form a food composition, A21 or A23; compounds in general, see the relevant compound class, e.g. C01, C07)}
- C12Y: ENZYMES

## Abstract

The present invention relates to novel DNA sequences that encode for the branched-chain alpha-ketoacid dehydrogenase complex of an organism belonging to the genus Streptomyces and to novel polypeptides produced by the expression of such sequences. It also relates to novel methods of enhancing the production of natural avermectin, of producing a Streptomyces avermitilis bkd mutant and of producing novel avermectins through fermentation.

## Claims

### Claim 1

A method of producing a natural avermectin comprising fermenting S. avermitilis in which the copy number of a genomic fragment comprising one or more of the bkdF, bkdG and bkdH genes has been increased.

### Claim 2 (depends on 1)

A method according to claim 1, comprising fermenting S. avermitilis in which the copy number of a genomic fragment comprising the bkdF, bkdG and bkdH genes have been increased.