Cytochrome b5 promotes the synthesis of delta 16-C19 steroids by homogeneous cytochrome P-450 C21 side-chain cleavage from pig testis

Conversion of progesterone to 17 alpha-hydroxyprogesterone plus androstenedione (17 alpha-hydroxylation) and to androstadienone (delta 16 synthetase activity) by microsomes from neonatal pig testis, were both inhibited by antibodies raised against homogeneous cytochrome P-450 C21 side-chain cleavage. Inhibition of the two activities showed the same relationship to the concentration of antibody added. Analogous results were obtained with pregnenolone as substrate. In a reconstituted enzyme system consisting of the homogeneous cytochrome P-450 C21 side-chain cleavage enzyme, P-450 reductase and NADPH, addition of cytochrome b5 resulted in the synthesis of the corresponding delta 16-C19-steroid from progesterone (androstadienone) and pregnenolone (androstadienol). The effect of cytochrome b5 was concentration-dependent and prevented by anti-cytochrome b5. It is concluded that the cytochrome P-450 C21 side-chain cleavage enzyme from pig testicular microsomes is also capable of synthesizing delta 16-C19-steroids and is, therefore, likely to be responsible for the large amounts of the pherormone androstadienone produced by male pigs.     

Complete amino acid sequence of a unique protein related to the variable domain of lambda light chain from a case with Fanconi syndrome

The complete amino acid sequence has been determined of a unique protein from a 55-years-old female with multiple myeloma associated with Fanconi syndrome. It existed in a monomer form with an apparent molecular weight of 10K daltons, and was consisted of 106 amino acid residues. The sequence was characteristic of the V-region of lambda light chains and was highly homologous with that of the first 106 residues of V lambda III subgroup. The presence of an intact light chain as well as a 13K daltons fragment, corresponding to the entire C-region, strongly suggests that the unique component is a catabolic product from the intact light chain rather than an aberrant product of synthesis.     

Characteristics of a Urate-Degrading Diamine Oxidase-Peroxidase Enzyme System in Soybean Radicles

The cadaverine content of soybean radicles showed a maximumpeak 3–4 days after planting. The variation coincidedwith radicle uricase activity during seed germination. The uricase activity could not be fractionate when the bufferpH for the extraction was at 6.0. The addition of 1 M KCl orNaCl to the buffer allowed the extraction of the uricase activity,but an addition of 1 M MgCl₂ or BaCl₂ inhibited this enzyme'sactivity. The urate-degrading enzyme system was purified 248-fold permilligram of protein from soybean radicles. The respective K_mvalues of the diamine oxidase activity for cadaverine and ofthe urate-degrading activity for hydrogen peroxide and uratewere 1.25, 2.93 and 50.3 µM. Analysis by gel electrophoresisof the partially purified enzyme fraction revealed that theurate-degrading enzyme system consisted of a peroxidase thatdegrades urate with hydrogen peroxide and a diamine oxidasethat releases hydrogen peroxide. These data are evidence that a urate-degrading diamine oxidaseand peroxidase system exists in soybean radicles and that thereaction rate of urate-degradation is controlled by the concentrationof cadaverine. (Received November 28, 1984; Accepted April 8, 1985)     

Length heterogeneity of the large spacer of Vicia faba rDNA is due to the differing number of a 325 bp repetitive sequence elements

Summary The DNA fragments including the whole large spacer region of Vicia faba rDNA were cloned in plasmid pBR325. Sixteen clones were classed into five groups which differed from each other in the lengths of the rDNA inserts. Physical maps of these length variants cloned were constructed using EcoRI, SalI, HpaI, MluI and AccI and evidence was obtained that the length heterogeneity was due mainly to the differing number of 325 base pairs (bp) subrepeating elements in the large spacer. Sequence analysis of this subrepeating element revealed that it consisted of a duplet of an approximately 155 bp sequence and a 14 bp unrelated sequence. This structure of the repetitive element is novel.     

Dispersion distance of queens from natal sites in the two haplometrotic paper waspsPolistes riparius andP. snelleni (Hymenoptera: Vespidae)

Dispersion capabilities of new queens were studied in the two haplometrotic paper wasps Polistes riparius and P. snelleni. New queens were marked on the nests in the late summer and located in the next spring. Dispersion distances greatly varied among queens: although a large part of recovered queens nested in close proximity to their natal sites, some did disperse over 100–300 m. This suggests that queens' emigration from and immigration into the censused areas occurred to a substantial extent. On the whole, these species exhibited a weaker “philopatric” tendency than those so far studied for dispersion distance, and seem to have the potential for a long-distance dispersion.     

Histamine release from rat mast cells by Vibrio vulnificus protease

Abstract Vibrio vulnificus protease (VVP) stimulated histamine release from isolated mast cells in a dose- and temperature-dependent manner within a range of 0.2–4.0 μ g/0.5 ml. Histamine release was accompanied by degranulation, and no leakage of lactate dehydrogenase from cells was observed, indicating that the histamine release was not due to cytolysis but to exocytosis. This release, completed within 30 s at 37°C, suggested that the mechanism of action of VVP on mast cells is different from that of other proteases, such as trypsin or α-chymotrypsin, which release histamine from the cells slowly.     

Cadaverine Involved in Urate Degrading Activity (Uricase Activity) in Soybean Radicles

Cadaverine, a 5-carbon diamine, was identified as the cofactorof uricase activity previously found in soybean seedlings. Thesubstance purified from freeze dried hypocotyls was subjectedto liquid chromatography, mass spectrometry, ¹H- and ¹³C-nuclearmagnetic resonance spectrometry for identification. The concentrationsof cadaverine in 3-day-old radicles and hypocotyls were 2.37mM and 5.09 mM, respectively. Other polyamine concentrationswere low. Biogenic polyamines (cadaverine, putrescine, spermidineand spermine) functioned as cofactors, whereas conjugated polyamines(tyramine and histamine) and amino acids had no effect. Theaddition of catalase to the assay system counteracted the effectof cadaverine. Peroxide at appropriate concentrations actedlike cadaverine with an identical K_m value, suggesting thaturate degrading activity can be ascribed to the diamine oxidase-peroxidasesystem. (Received October 19, 1982; Accepted December 23, 1982)     

Molecular Cloning and Restriction Analysis of EcoRI-fragments of Vicia faba rDNA

EcoRI-fragments of Vicia faba rDNA were cloned in plasmid pBR325.Southern blot hybridization of BamHI-digests of these clonedplasmids and Vicia genomic DNA led to the determination of relativepositions of BamHl sites in the rDNA and the physical map thathad been tentatively made is corrected. (Received May 20, 1982; Accepted July 13, 1983)