1. The rate of oxidative deamination of 1,5-diaminopentane by pea-seedling extracts, which contain diamine oxidase [diamine-oxygen oxidoreductase (deaminating), EC 1.4.3.6], was increased by adding pyridoxal or pyridoxal phosphate. 2. Evidence was obtained that pyridoxal does not activate the apoenzyme of diamine oxidase, but prevents the inactivation of the enzyme. 3. This inactivation only occurred when 1,5-diaminopentane was the substrate and depended on a second thermolabile factor in the extract besides the diamine oxidase. 4. Purified diamine oxidase, when catalysing the oxidation of 1,5-diaminopentane, was rapidly inactivated in the presence of peroxidase. 5. The inactivation was prevented not only by pyridoxal and pyridoxal phosphate but also by several unrelated compounds including alpha-oxoglutarate, catechol and o-aminobenzaldehyde. 6. It is suggested that peroxidase catalyses the further oxidation of the product of the oxidative deamination of 1,5-diaminopentane to a compound that inactivates diamine oxidase. 7. The results diminish the relevance of previous evidence that plant diamine oxidase contains pyridoxal phosphate.
E. ccili L-asparaginase 250 and 500 U/kg given in.a ~ingle I ~V dose did not produce hyperglycemia or g1ycosuna In rabblts. Prednisolone 1 mg/kg/day administered for 14 days was also nondiabetogenic. A combination of L-asparaginase 500 U/Ieg with prednisolone was diabetogenic in all the animals. The results suggest that the two drugs act synergistically in producing the diabetogenic effect The clinical significance oe these fmdings was discussed.
The cutaneous application of antiviral agents was studied by iontophoresis, a process that increases penetration of most drugs 20- to 60-fold. Twenty-seven subjects with vesicular orolabial herpes were treated one time in a double-blind, placebo-controlled clinical study: nine received vidarabine monophosphate (ara-AMP), nine received acyclovir (ACV), and nine received NaCl. Ara-AMP-treated lesions yielded lower titers of virus after 24 hr compared with lesions treated with NaCl or ACV (P less than .05). Ara-AMP significantly decreased the duration of shedding of virus (P less than .05) and time to dry crust (P less than .05) compared with the other two agents. There was a trend toward decreased healing time after ara-AMP treatment.
Renal hypertrophy, induced by uninephrectomy (UNi), results in a 40 50% increase in the RNA content per cell 4 days postoperatively (1). Virtually no change in the DNA content occurs over the 4-day period (2). During the first 4 days of renal hypertrophy, incorporation of labeled nucleosides (uridine, orotate, and cytidine) into RNA showed no increase. Rates of synthesis of total kidney RNA from UNI mice, determined by measuring the labeling rates of RNA and UTP, showed no increase when compared to shams (3).Since the rate of synthesis is unchanged after UNI, the accretion of rRNA could occur by a decrease in degradation. However, the half-life of rRNA labeled before UNI is identical to sham value. Apparently RNA accretion during kidney hypertrophy does not occur by increased rate of transcription or decreased degradation of rRNA. These facts are compatible with the hypothesis that excess production and rapid degradation of newly synthesized rRNA occurs in the unstimulated kidney and that during renal hypertrophy the degradation is reduced. Other investigators have evidence of a similar phenomenon in the estrogenstimulated uterus (4), phytohemagglutininstimulated lymphocytes (5, 6), regenerating liver 260 THE JOURNAl. OF CH.t. Blot.oo ', 9 Vc, t.u~'u: 64. 1975 9 pages 260-265 on
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.