Aminations of guanosine and deoxyguanosine with hydroxylamine-O-sulfonic acid and 2,4-dinitrophenoxyamine. Dependence on the reaction medium.

Amination of guanosine (Guo) with 2,4-dinitrophenoxyamine in aqueous DMF gave 7-amino-Guo, which was readily converted to 8,5'-O-cyclo-Guo, and 8-hydroxy-Guo. Deoxyguanosine (dG) gave only deglycosylated 7-amino-G under the same reaction condition. Aminations of Guo and dG with hydroxylamine-O-sulfonic acid above pH 9 gave the corresponding 1-amino derivatives, whereas those in acidic media at pH 2-4 gave 8-amino-Guo and 7-amino-G as the main products, respectively.

Studies on chemical carcinogens and mutagens. XXIX. Mutagenic N-trimethylsilylmethyl-N-nitrosourea as a biological alkylating agent equivalent to N-methyl-N-nitrosourea (MNU).

N-Trimethylsilylmethyl-N-nitrosourea (TMS-MNU), a silicon analogue of N-neopentyl-N-nitrosourea (neoPNU), was assayed for mutagenicity and/or cytotoxicity on a series of E. coli B tester strains, S. typhimurium TA100, Chinese hamster V79, and cultured murine leukemia L1210 cells.

Biomimetic preparation and structure determination of QGI, one of the quinoline-DNA base adducts formed in cells treated with 4-nitroquinoline 1-oxide.

One of the quinoline-DNA base adducts, QGI, formed in cells treated with 4-nitroquinoline 1-oxide, was readily prepared in vitro from GMP or dGMP and 4-hydroxy-aminoquinoline 1-oxide in the presence of ATP, L-serine, and seryl tRNA synthetase. Synthetic seryl-AMP could be substituted for the enzymatic activation system for QGI formation. Chemical and spectral analyses of the adduct thus prepared revealed that QGI can be formulated as N4-(guan-8-yl)-4-aminoquinoline 1-oxide, the structure of which is identical with the modified base structure involved in the deoxyguanosine-quinoline adduct, dGIII (nomenclature of Loucheux-Lefebvre et al.

Automated enzymatic determination of serum and urine creatine using the Abbott ABA-200.

A new enzymatic method is described for the determination of creatine in serum and urine with Abbott ABA-200. The measurement is accomplished by transforming creatine to formic acid in a reaction catalyzed by creatinase (creatine amidinohydrolase), sarcosine oxidase and formaldehyde dehydrogenase (see Figure 1). The assay takes less than 20 minutes.

Semi-automated continuous-flow enzyme immunoassay for antiepileptic drugs in serum.

We have developed a semi-automated method for measuring five kinds of antiepileptic drugs in serum by successfully adapting commercial competitive-binding enzyme immunoassay kits (MARKIT; Dainippon) for use with a continuous-flow analyzer (Technicon AutoAnalyzer II equipped with a dialyzer). The free enzyme-labeled drug is automatically separated by a microfilter from the competitive immunoreaction mixture between labeled and unlabeled drug for anti-drug immunoglobulin coupled to bacterial cell walls. The concentrations of the antiepileptic drugs in serum samples can be determined by automated measurement of enzyme activity of the enzyme-labeled drugs.

A new enzymatic method to determine creatine.

A new enzymatic method is described for the determination of creatine in serum and urine using creatine amidinohydrolase (EC 3.5.3.

Assays of serum lipase by the "BALB-DTNB method" mechanized for use with discrete and continuous-flow analyzers.

We successfully adapted the dimercaprol (BAL) tributyrate-5,5'-dithiobis(2-nitrobenzoic acid) method (J. Biochem. 81: 361, 1977) for assay of lipase in human serum to a discrete analyzer (the TBA 880) (I) or a continuous-flow analyzer (AutoAnalyzer, Type II) (II).

Continuous-flow enzymic determination of creatine in urine.

A new enzymic method is described for the determination of creatine in urine by continuous-flow analysis. The measurement is accomplished by transforming creatine to formaldehyde in reactions catalyzed by creatinase (creatine amidinohydrolase) and sarcosine dehydrogenase. The formaldehyde is reacted with 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole to form a purple product, which is measured colorimetrically.

Various antigenic reactivities in delayed hypersensitivity among crystalline proteins from Mycobacterium phlei.

Comparisons were made of the delayed-type skin reactivity of 6 crystalline proteins purified from the cell extract of Mycobacterium phlei in guinea pigs sensitized with whole cells of the heat-killed bacillus. These highly purified proteins elicited varying degrees of cutaneous reaction. The most active protein had almost the same reactivity as purified protein derivative prepared from the culture filtrate of Mycobacterium phlei.