title: Biochemical and enzymatic study of rice BADH wild-type and mutants: an insight into fragrance in rice.
abstract: Betaine aldehyde dehydrogenase 2 (BADH2) is believed to be involved in the accumulation of 2-acetyl-1-pyrroline (2AP), one of the major aromatic compounds in fragrant rice. The enzyme can oxidize ω-aminoaldehydes to the corresponding ω-amino acids. This study was carried out to investigate the function of wild-type BADHs and four BADH2 mutants: BADH2_Y420, containing a Y420 insertion similar to BADH2.8 in Myanmar fragrance rice, BADH2_C294A, BADH2_E260A and BADH2_N162A, consisting of a single catalytic-residue mutation. Our results showed that the BADH2_Y420 mutant exhibited less catalytic efficiency towards γ-aminobutyraldehyde but greater efficiency towards betaine aldehyde than wild-type. We hypothesized that this point mutation may account for the accumulation of γ-aminobutyraldehyde/Δ(1)-pyrroline prior to conversion to 2AP, generating fragrance in Myanmar rice. In addition, the three catalytic-residue mutants confirmed that residues C294, E260 and N162 were involved in the catalytic activity of BADH2 similar to those of other BADHs.
authors.affiliation: Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand.
authors.forename: Ratree
authors.initials: R
authors.lastname: Wongpanya
authors.forename: Nonlawat
authors.initials: N
authors.lastname: Boonyalai
authors.forename: Napaporn
authors.initials: N
authors.lastname: Thammachuchourat
authors.forename: Natharinee
authors.initials: N
authors.lastname: Horata
authors.forename: Siwaret
authors.initials: S
authors.lastname: Arikit
authors.forename: Khin Myo
authors.initials: KM
authors.lastname: Myint
authors.forename: Apichart
authors.initials: A
authors.lastname: Vanavichit
authors.forename: Kiattawee
authors.initials: K
authors.lastname: Choowongkomon
mesh_terms: D000447:Aldehydes / Q000378:metabolism; D050728:Betaine-Aldehyde Dehydrogenase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D055162:Biocatalysis; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D012275:Oryza / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D017354:Point Mutation; D011758:Pyrroles / Q000378:metabolism
chemical_list: D000447:Aldehydes; D010940:Plant Proteins; D011758:Pyrroles; C006509:4-aminobutyraldehyde; D050728:Betaine-Aldehyde Dehydrogenase; C426303:2-acetyl-1-pyrroline