NADP(+)-dependent aminoalcohol dehydrogenase (AADH) of Rhodococcus erythropolis MAK154 catalyzes the reduction of (S)-1-phenyl-1-keto-2-methylaminopropane ((S)-MAK) to d-pseudoephedrine, which is used as a pharmaceutical. AADH is suggested to participate in aminoalcohol or aminoketone metabolism in this organism because it is induced by the addition of several aminoalcohols, such as 1-amino-2-propanol. Genetic analysis of around the aadh gene showed that some open reading frames (ORFs) are involved in this metabolic pathway. Four of these ORFs might form a carboxysome-like polyhedral organelle, and others are predicted to encode aminotransferase, aldehyde dehydrogenase, phosphotransferase, and regulator protein. OrfE, a homologous ORF of the FadR subfamily of GntR transcriptional regulators, lies downstream from aadh. To investigate whether or not orfE plays a role in the regulation of aadh expression, the gene disruption mutant of R. erythropolis MAK154 was constructed. The ΔorfE strain showed higher AADH activity than wild-type strain. In addition, a transformed strain, which harbored multi-orfE, showed no AADH activity even in the induced condition with 1-amino-2-propanol. These results suggest that OrfE is a negative regulator that represses aadh expression in the absence of 1-amino-2-propanol.

Aim:  A novel NADP+‐dependent l‐1‐amino‐2‐propanol dehydrogenase was isolated from Rhodococcus erythropolis MAK154, and characterized. Methods and Results:  The enzyme was inducibly produced on cultivation with aminoalcohols such as 1‐amino‐2‐propanol, 1‐amino‐2‐butanol and 2‐aminocyclohexanol. The enzyme catalyses the NADP+‐dependent oxidation of several aminoalcohols, and also the NADPH‐dependent asymmetric reduction of an aminoketone compound to a double chiral aminoalcohol, d‐pseudoephedrine. Amino acid sequence analysis showed that the enzyme might belong to the short‐chain dehydrogenase/reductase family. Conclusions:  NADP+‐dependent l‐1‐amino‐2‐propanol dehydrogenase isolated from R. erythropolis MAK154 reversibly catalysed dehydrogenation of aminoalcohols, and exhibited a unique sterospecifity for the reduction reaction. Significance and Impact of the Study:  The enzyme is a promising catalyst for the production of double chiral compound, d‐pseudoephedrine, from prochiral substrate.

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Westudied the relationship between various T lymphocyte functions and granuloma formation in 5 lung tissue and 4 lymph node tissue samples from patients with sarcoidosis by immunohistological methods. In the lesion of sarcoidosis, T cells were positive for apTCR, but y8TCR-positive T cells were rarely observed. The results of analysis of functional subsets showed that T cells in the internal area of granuloma were predominantly helper/inducer subset (CD4+ CD45RA). On the other hand, cytotoxic T cells (CD8+CD45RACDllb ) were present in abundance in the outer boundaries ofgranuloma. In addition, suppressor-inducer T cells (CD4+CD45RA+) were present in the surrounding areas. However,T cells of various subsets were present sporadically outside the granulomas. Wealso studied the distribution of T cells expressing activationrelated antigens. The results showed that T lymphocytes in the internal area of granulomas more frequently had these antigens than did T lymphocytes in the external area. These findings suggested that T cells infiltrating into the sarcoidosis lesion demonstrated a layer-like distribution based on functional subsets. These findings also confirm that activated T cells were more abundantly distributed in the internal area of sarcoid granuloma than in the external area. (Internal Medicine 34: 847-855, 1995)

The gene encoding NADP(+)-dependent L-1-amino-2-propanol dehydrogenase (AADH) of Rhodococcus erythropolis MAK154 was cloned and sequenced. A 780-bp nucleotide fragment was confirmed to be the gene encoding AADH by agreement of the N-terminal and internal amino acid sequences of the purified AADH. The gene (aadh) codes a total of 259 amino acid residues, and the deduced amino acid sequence shows similarity to several short-chain dehydrogenase/reductase family proteins. An expression vector, pKKAADH, which contains the full length aadh was constructed. Escherichia coli cells possessing pKKAADH exhibited a 10.4-fold increase in specific activity as to catalysis of the reduction of (S)-1-phenyl-2-methylaminopropan-1-one (MAK), as compared with that of R. erythropolis MAK154 induced by 1-amino-2-propanol (1 mg/ml). Coexpression of aadh with a cofactor regeneration enzyme (glucose dehydrogenase) gene was also performed, and a system for sufficient production of d-pseudoephedrine from racemic MAK was constructed.