Inhibition of nitric oxide synthesis by NG-nitro-L-arginine methyl ester (L-NAME): requirement for bioactivation to the free acid, NG-nitro-L-arginine
摘要:
The L‐arginine derivatives NG‐nitro‐L‐arginine (L‐NOARG) and NG‐nitro‐L‐arginine methyl ester (L‐NAME) have been widely used to inhibit constitutive NO synthase (NOS) in different biological systems. This work was carried out to investigate whether L‐NAME is a direct inhibitor of NOS or requires preceding hydrolytic bioactivation to L‐NOARG for inhibition of the enzyme.A bolus of L‐NAME and L‐NOARG (0.25 μmol) increased coronary perfusion pressure of rat isolated hearts to the same extent (21 ± 0.8 mmHg; n = 5), but the effect developed more rapidly following addition of L‐NOARG than L‐NAME (mean half‐time: 0.7 vs. 4.2 min). The time‐dependent onset of the inhibitory effect of L‐NAME was paralleled by the appearance of L‐NOARG in the coronary effluent.Freshly dissolved L‐NAME was a 50 fold less potent inhibitor of purified brain NOS (mean IC50 = 70 μm) than L‐NOARG (IC50 = 1.4 μm), but the apparent inhibitory potency of L‐NAME approached that of L‐NOARG upon prolonged incubation at neutral or alkaline pH. H.p.l.c. analyses revealed that NOS inhibition by L‐NAME closely correlated with hydrolysis of the drug to L‐NOARG.Freshly dissolved L‐NAME contained 2% of L‐NOARG and was hydrolyzed with a half‐life of 365 ± 11.2 min in buffer (pH 7.4), 207 ± 1.7 min in human plasma, and 29 ± 2.2 min in whole blood (n = 3 in each case). When L‐NAME was preincubated in plasma or buffer, inhibition of NOS was proportional to formation of L‐NOARG, but in blood the inhibition was much less than expected from the rates of L‐NAME hydrolysis. This was explained by accumulation of L‐NOARG in blood cells.These results suggest that L‐NAME represents a prodrug lacking NOS inhibitory activity unless it is hydrolyzed to L‐NOARG. Bioactivation of L‐NAME proceeds at moderate rates in physiological buffers, but is markedly accelerated in tissues such as blood or vascular endothelium.
An efficient parallel synthesis of ureas based on amino acids is described, both in solution and on solidphase. 1,1′-Carbonylbisbenzotriazole 2 is used as the coupling reagent. The ureas 5 and 10 were obtained in high yield (80–100%) and purity (71–97%).
COMPOSITIONS AND METHODS USEFUL FOR REDUCING THE VISCOSITY OF PROTEIN-CONTAINING FORMULATIONS
申请人:Genentech, Inc.
公开号:US20130058958A1
公开(公告)日:2013-03-07
The invention relates to use of certain compounds including, for example, certain charged amino acids and structural analogs thereof, for reducing the viscosity of aqueous protein-containing formulations. Associated compositions of matter and methods of use are also contemplated within the present invention.
[EN] METHODS AND COMPOSITIONS FOR INCREASING TOLERANCE TO ABIOTIC STRESS IN PLANTS<br/>[FR] PROCÉDÉS ET COMPOSITIONS CONSISTANT À AUGMENTER LA TOLÉRANCE AU STRESS ABIOTIQUE CHEZ DES VÉGÉTAUX
申请人:CROP MICROCLIMATE MAN INC
公开号:WO2019152632A1
公开(公告)日:2019-08-08
The present invention relates to compositions and methods for increasing tolerance to abiotic stress and/or for reducing the consequence of abiotic stress in a plant and/or part thereof. In some aspects, the method comprises contacting a plant and/or part thereof with a first composition comprising one or more of aminoguanidine, L-nitroarginine, L-nitroarginine methyl ester, 2,2'-bipyridine, 4-methylpyrazole, 8-hydroxyquiniline, caprylic acid, pyrazole, naringenin, kaempferol, quercetin, dodecanoic acid, and/or undecanoic acid, and/or a salt thereof; and a second composition comprising at least one dicarboxylic acid and/or a salt thereof.