Akihiko Nomura

A variety of catalases and bromoperoxidases in genus Pseudomonas and their characterization.

A survey of bromoperoxidase in some Pseudomonas strains revealed that they contain different types of bromoperoxidase, catalase-bromoperoxidase and catalase. Although all Pseudomonas strains exhibited catalase activity, the enzyme isolated from P. pyrrolnitrica was named catalase-bromoperoxidase, because it catalyzed not only a catalase reaction, but also the bromination of monochlorodimedone. Except heme-type catalase-bromoperoxidase, this strain contained four isoenzymes of general nonheme bromoperoxidase, and their molecular weights were about 73,000. On the other hand, P. putida and P. aeruginosa had the usual heme-type catalase, but they differed in molecular weight and pI value. Both strains also had a nonheme bromoperoxidase which catalyzed the bromination of monochlorodimedone and aniline, and the molecular weight of each enzyme was 68,000 for P. putida and 86,000 for P. aeruginosa. Considering the results reported by Van Pée et al. [1] and Weisner et al. [2], regarding the haloperoxidases of Pseudomonas, the genus was revealed to contain a wide variety of bromoperoxidase and catalase.

Studies on the Chemical Synthesis of Potential Antimetabolites. 36. Synthesis and Some Biochemical Properties of (±)1-Deazaaristeromycin

Abstract Chemical synthesis of a carbocyclic nucleoside, (±)1-deaza-aristeromycin (1), is described. Compound 1 was found to possess only a weak inhibitory effect on calf intestine adenosine deaminase. For rabbit liver S-adenosylhomocysteinase 1 showed weak affinity but acted as a potent irreversible inactivator.

Studies on the Chemical Synthesis of Potential Antimetabolites. 35.1 Synthesis of 2-Chloro-1-deazaadenosine and 2-Chloro-1-deazainosine as Candidate Inhibitors for S-Adenosylhomocysteinases and Methyltransferases

Abstract The syntheses of 2-chloro-1-deazaadenosine (2) and 2-chloro-1-deazainosine (3) are described. Conversion of 7-ribosylated 6-chloro-1-deazapurine 3-oxide to the desired 2,6-disubstituted 9-ribosyl-1-deazapurines was effected by a series of reactions involving “deoxygenative chlorination” and transglycosylation in satisfactory yields.

Studies on transfer RNAs I. A novel method for selective deamination of cytosines in oligonucleotides and transfer RNA

1. 1. Treatment of N4-hydroxycytosines with oxidizing agents (viz. sodium metaperiodate, or potassium bichromate) under mild conditions gave rise to the corresponding uracil derivatives. 2. 2. Specific deamination of cytosine residues into uracil residues in oligonucleotides has been achieved by a combination of hydroxylamination and subsequent oxidation. Thus, under mild conditions CpA, CpGp and ApApCp could be converted into UpA, UpGp and ApApUp in satisfactory yields, respectively. 3. 3. By this novel procedure, approx. 20% of the cytosine residues in unfractionated Torula yeast tRNA could be converted into uracil residues. These modified tRNA showed valine acceptor activity.

Studies on the Chemical Synthesis of Potential Antimetabolites. 371. Synthesis of 3-Deazaadenine Nucleosides Modified at the Sugar Moiety

Abstract Several types of 3-deazaadenine pentofuranosides, represented by 9-(3-deoxy-β-D-glycero-pent-3-enofuranosyl)-3-deazaadenine (1), 9-(5-deoxy-β-Q-erythro-pent-4-enofuranosyl)-3-deazaadenine (2) and 9-β-D-xylo-furanosyl-3-deazaadenine (3), were prepared starting from 6-chloro-9-β-D-ribofuranosyl-3-deazaadenine (4).