Provided are a transaminase mutant and an application thereof. Compared with an amino acid sequence shown in SEQ ID NO:1, an amino acid sequence of the transaminase mutant includes at least one of the following mutation sites: L166, K149, K146, A168, H73, F133, H82, E24, V194, T294, A295, G235 and F236. The mutant of the present invention has the improved catalytic activity for a transammonization reaction of ketone substrates, and is suitable for industrial production of chiral amines.

A microorganism is transformed to be capable of producing guanidinoacetic acid (GAA). A method can be used for the fermentative production of GAA using such a microorganism. A corresponding method can be used for the fermentative production of creatine.

Provided are a transaminase mutant and use thereof. The transaminase mutant has an amino acid sequence obtained by mutation of an amino acid sequence shown in SEQ ID NO:1, the mutation at least includes one of the following mutation site combinations: T7C+S47C, Q78C+A330C, V137C+G313C, A217C+Y252C and L295C+C328C; or the transaminase mutant has an amino acid sequence which has the mutation sites in the mutated amino acid sequence and has 80% or more identity with the mutated amino acid sequence. The transaminase mutant realizes the change of protein structure and functions, reduces the enzyme amount, increases the enantiomeric excess (ee) value of a product, and reduces the difficulty of post-processing, so that the transaminase mutant may be suitable for industrial production.

The present disclosure provides engineered transaminase enzymes having improved properties as compared to a naturally occurring wild-type transaminase enzyme. Also provided are polynucleotides encoding the engineered transaminase enzymes, host cells capable of expressing the engineered transaminase enzymes, and methods of using the engineered transaminase enzymes to synthesize a variety of chiral compounds.

Provided are a polypeptide having excellent 4-aminobenzoic acid hydroxylation activity and a method for using the same. The present invention provides a polypeptide having 4-aminobenzoic acid hydroxylation activity, consisting of the amino acid sequence represented by SEQ ID NO: 2 or an amino acid sequence having at least 47% identity thereto, and having an amino acid residue at position 47 of the amino acid sequence represented by SEQ ID NO: 2 or a position corresponding thereto being leucine.

Provided are a microorganism that produces a diamine compound and a method of producing a diamine compound.

The genetically modified microorganism expresses an enzyme involved in synthesis of a diamine compound, in which the diamine compound is represented by Formula: H.sub.2N—R—NH.sub.2 (wherein, R is a chain or cyclic organic group comprised of one or more atoms selected from the group consisting of C, H, O, N, and S), and the genetically modified microorganism is modified to reduce an activity of an alcohol dehydrogenase compared to a non-reduced strain.

The present invention discloses a transaminase mutant and application thereof in preparation of sitagliptin intermediates, the transaminase mutant is obtained by substitution of tyrosine with proline at position 74, substitution of glutamic acid with aspartic acid at position 228, substitution of leucine with alanine at position 254 and substitution of methionine with threonine at position 290 of the amino acid sequence shown in SEQ ID NO: 2. The present invention uses wet cells or a purified transaminase as a biocatalyst and a sitagliptin precursor ketone or a prochiral carbonyl compound as a substrate to prepare a sitagliptin intermediate or a sitagliptin ester intermediate; the total yield of the method reaches about 82%, and e.e. value of the product reaches 99%.

An amino acid sequence of the transaminase mutant is an amino acid sequence obtained by a mutation of an amino acid sequence is shown in SEQ ID NO: 1. The mutation occurred at least one of the following mutation sites: G17V, L36P, Q40H, G69Y, H70T, L73A, V77G, V77S, V77T, A78I, Y130M, Y130V, Y130T, N132I, N132T, K141S, K142S, K142T, R143P, G144F, G144W, G144Y, E145D, E145S, E145G, K146R, L148A, L148I and the like.

Use of a stereoselective transaminase in the asymmetric synthesis of a chiral amine. In particular, provided is use of a polypeptide in the production of a chiral amine or a downstream product using a chiral amine as a precursor. Further provided is a method for producing a chiral amine, comprising culturing a strain expressing the polypeptide so as to obtain a chiral amine. Further provided are a chiral amine production strain and a method for constructing the chiral amine production strain. The stereoselective transaminase has a broad substrate spectrum and thus has a broad application potential in the preparation of a chiral amine.

The present disclosure relates to transaminase polypeptides capable of aminating a dicarbonyl substrate, and polynucleotides, vectors, host cells, and methods of making and using the transaminase polypeptides.