An imine reductase mutant, including a mutation in an amino acid sequence represented by SEQ ID NO: 1. The mutation in the amino acid sequence includes V171, A172, Y230, or a combination thereof. Also provided is a method for preparing (S)-nicotine, including: under suitable conditions, catalytically reducing a substrate I to (S)-nornicotine by the imine reductase mutant, and methylating (S)-nornicotine to yield (S)-nicotine.

The present application provides engineered polypeptides having imine or oxime reductase activity, polynucleotides encoding the engineered polypeptides, host cells capable of expressing the engineered polypeptides, and methods of using these engineered polypeptides with a range of ketone and amine substrate compounds to prepare secondary and tertiary amine product compounds.

Provided are a resistant protein for use in herbicide dicamba, encoding gene and application thereof, the gene comprising: (a) a nucleotide sequence of an amino acid sequence as shown in SEQ ID NO: 2; or (b) a nucleotide sequence which is complementary to the nucleotide sequence as defined by (a) under stringent conditions; or (c) a nucleotide sequence as shown in SEQ ID NO: 1.

The present disclosure provides engineered polypeptides having imine reductase activity, polynucleotides encoding the engineered imine reductases, host cells capable of expressing the engineered imine reductases, and methods of using these engineered polypeptides with a range of ketone and amine substrate compounds to prepare secondary and tertiary amine product compounds.

The invention discloses a method for increasing the yield of L-arginine by knocking out flavin reductases, and belongs to the technical field of amino acid production by microbial fermentation. Genes frd1 and frd2 for encoding hypothetic NADPH-dependent FMN reductase in Corynebacterium crenatum SDNN403 are over-expressed in E. coli BL21 and are purified to form target proteins Frd181 and Frd188, and functions of the target proteins are identified to obtain a result showing that the proteins Frd181 and Frd188 both are NAD(P)H-dependent flavin reductases producing H.sub.2O.sub.2. By taking a genome of the Corynebacterium crenatum SDNN403 as a template, frd1 and frd2 gene deletion fragments are obtained by overlap extension PCR; connecting pK18mobsacB to obtain knockout plasmids pK18mobsacB-frd1 and pK18mobsacB-frd2; carrying out electric shock to transform the Corynebacterium crenatum SDNN403; and carrying out secondary screening to obtain recombinant strains 403frd1 and 403frd2. Found by flask shaking fermentation, the yield of L-arginine is obviously increased by knocking out the genes frd1 and frd2.

A method of demethylizing an opioid to a nor-opioid is provided. The method comprises contacting an opioid with at least one enzyme. Contacting the opioid with the at least one enzyme converts the opioid to a nor-opioid. A method of converting a nor-opioid to a nal-opioid is provided. The method comprises contacting a nor-opioid with at least one enzyme. Contacting the nor-opioid with the at least one enzyme converts the nor-opioid to a nal-opioid.

Provided herein is a non-naturally occurring microbial organism having a methanol metabolic pathway that can enhance the availability of reducing equivalents in the presence of methanol. Such reducing equivalents can be used to increase the product yield of organic compounds produced by the microbial organism, such as 3-hydroxyisobutyrate or MAA. Also provided herein are methods for using such an organism to produce 3-hydroxyisobutyrate or MAA.

The present application provides engineered polypeptides having imine reductase activity, polynucleotides encoding the engineered imine reductases, host cells capable of expressing the engineered imine reductases, and methods of using these engineered polypeptides with a range of ketone and amine substrate compounds to prepare secondary and tertiary amine product compounds.

The present application provides engineered polypeptides having imine or oxime reductase activity, polynucleotides encoding the engineered polypeptides, host cells capable of expressing the engineered polypeptides, and methods of using these engineered polypeptides with a range of ketone and amine substrate compounds to prepare secondary and tertiary amine product compounds.

The present disclosure provides engineered polypeptides having imine reductase activity, polynucleotides encoding the engineered imine reductases, host cells capable of expressing the engineered imine reductases, and methods of using these engineered polypeptides with a range of ketone and amine substrate compounds to prepare secondary and tertiary amine product compounds.