scholarly journals The altered specificity of cortisone reductase with certain retroandrostan-3-one substrates

1975 ◽  
Vol 145 (3) ◽  
pp. 483-489 ◽  
Author(s):  
W Gibb ◽  
J Jeffery ◽  
David N. Kirk ◽  
H Mahdi
Keyword(s):  
Absolute Configuration ◽  
Substrate Recognition ◽  
Hydroxyl Group ◽  
Appreciable Amount ◽  
Hydroxy Compound ◽  
Structure Activity Relationships ◽  
Good Substrate ◽  
Structure Activity ◽  
The Absolute ◽  
Hydroxy Compounds

The retro steroids 17beta-hydroxy-5beta,9beta,10alpha-androstan-3-one and 5beta,9beta,10alpha-androstane-3,17-dione were good substrates for cortisone reductase in the presence of NADH, and the products corresponded to the respective 3beta-hydroxy compounds, in which the 3beta-hydroxyl group is axial and the absolute configuration is 3S. The analogous natural steroids 17beta-hydroxy-5beta,9alpha,10beta-androstan-3-one and 5beta,9alpha,10beta-androstane-3,17-dione were very poor substrates, and gave the corresponding 3alpha(equatorial,3R)-hydroxy compounds, and, in the latter case, also an appreciable amount of 3beta(axial, 3S)-hydroxy-5beta,9alpha,10beta-androstan-17-one. The natural steroids 17beta-hydroxy-5alpha,9alpha,10beta-androstan-3-one and 5alpha,9alpha,10beta-androstane-3,17-dione were better substrates than the retro steroid 17beta-hydroxy-5alpha,9beta,10alpha-androstan-3-one, but were not such good substrates as the retro steroids 17beta-hydroxy-5beta,9beta,10alpha-androstan-3-one and 5beta,9beta,10alpha-androstane-3,17-dione. Unlike these retro steroid 5beta,9beta,10alpha-androstan-3-ones, the natural steroids 17beta-hydroxy-5alpha,9alpha,10beta-androstan-3-one and 5alpha,9alpha,10beta-androstane-3,17-dione gave the corresponding 3alpha(axial,3R)-hydroxy compounds. The retro steroid 17beta-hydroxy-5alpha,9beta,10alpha-androstan-3-one was not a good substrate, and the product of reaction corresponded to the 3alpha(axial,3R)-hydroxy compound. The nature of substrate recognition by this enzyme is discussed in the light of these structure-activity relationships.

Structure–activity relationships for substrate recognition by the human dopamine transporter

2004 ◽  
Vol 67 (2) ◽  
pp. 293-302 ◽  
Author(s):  
Michael Appell ◽  
Janet L. Berfield ◽  
Lijuan C. Wang ◽  
William J. Dunn ◽  
Nianhang Chen ◽  
...  
Keyword(s):  
Dopamine Transporter ◽  
Substrate Recognition ◽  
Structure Activity Relationships ◽  
Structure Activity

scholarly journals DPPH-Scavenging Activities and Structure-Activity Relationships of Phenolic Compounds

2010 ◽  
Vol 5 (11) ◽  
pp. 1934578X1000501 ◽  
Author(s):  
Cheng-Dong Zheng ◽  
Gang Li ◽  
Hu-Qiang Li ◽  
Xiao-Jing Xu ◽  
Jin-Ming Gao ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Antiradical Activity ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Basic Structure ◽  
Hydroxyl Group ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Dpph Scavenging ◽  
Dpph Radical Scavenging

Thirty-eight phenolic compounds (including 31 flavonoids) were examined for their DPPH radical-scavenging activities, and structure-activity relationships were evaluated. Specifically, the presence of an Ortho-dihydroxyl structure in phenolics is largely responsible for their excellent antiradical activity. 3-Hydroxyl was also essential to generate a high radical-scavenging activity. An increasing number of hydroxyls on flavones with a 3′,4′-dihydroxyl basic structure, the presence of a third hydroxyl group at C-5′, a phloroglucinol structure, glycosylation and methylation of the hydroxyls, and some other hydroxyls, for example 5-, and 7-hydroxyl in ring A, decreased the radical-scavenging activities of flavonoids and other phenolics.

Structure-activity relationships of sparsomycin: modification at the hydroxyl group

Biochimie ◽  
1987 ◽  
Vol 69 (8) ◽  
pp. 849-856 ◽  
Author(s):  
Ester Lazaro ◽  
Leon A.G.M Van Den Broek ◽  
Harry C.J. Ottenheijm ◽  
Peter Lelieveld ◽  
Juan P.G. Ballesta
Keyword(s):  
Hydroxyl Group ◽  
Structure Activity Relationships ◽  
Structure Activity

Effect of reserpine on the structure–activity relationships for the inhibition of noradrenaline uptake in adrenergic nerves in rat and rabbit ventricle by phenethylamines

1977 ◽  
Vol 55 (2) ◽  
pp. 196-205 ◽  
Author(s):  
D. M. Paton ◽  
D. S. Golko
Keyword(s):  
Phenolic Hydroxyl ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Noradrenaline Uptake ◽  
Inhibitory Potency ◽  
Sympathomimetic Amines ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Phenolic Hydroxyl Groups ◽  
Inhibitory Agents

Ventricular tissue from the hearts of normal and reserpine-pretreated rats and rabbits were exposed to pargyline, tropolone, and hydrocortisone to inhibit monoamine oxidase (EC 1.4.3.4), catechol-O-methyltransferase (EC 2.1.1.6), and extraneuronal uptake, respectively. To examine the structure–activity relationships for inhibition of noradrenaline uptake, the inhibition of the 10-min uptake of (−)-[3H]noradrenaline by sympathomimetic amines was determined and ID50 values calculated. In reserpine-pretreated tissues, the most potent inhibitory agents studied were amines lacking phenolic hydroxyl groups (i.e., β-phenethylamine, (+)- and (−)-amphetamine). Addition of one or two phenolic hydroxyl groups, a β-hydroxyl group, or an N-methyl group generally decreased inhibitory potency, while α-methylation had little effect. Amines with large N-substitution and phenolic O-methyl groups were the least potent inhibitory agents. The stereoisomers of amphetamine, noradrenaline, and metaraminol did not differ in potency. However, the stereoisomers of ephedrine did, the order of potency being (−)-ephedrine > (±)-ephedrine > (+)-ψ-ephedrine > (−)-ψ-ephedrine. These structure–activity relationships are the same as those previously found for the acceleration of efflux of extragranular noradrenaline. Amines also released (−)-[3H]noradrenaline from reserpine-pretreated tissues. Results obtained using ventricles from nonreserpinized rats and rabbits showed two important differences. Firstly, sympathomimetic amines were much less potent releasers of (−)-[3H]noradrenaline from such tissues. Secondly, amines lacking phenolic hydroxyl groups were, on the average, five- to seven-fold less potent as inhibitors of (−)-[3H]-noradrenaline uptake. However, the inhibitory potencies of phenolethylamines and catecholamines were generally similar to those found in reserpine-pretreated tissues. These studies have demonstrated that reserpine pretreatment potentiates the inhibitory potency of phenethylamines and phenylethanolamines.

scholarly journals Study on structure–activity relationships (SARs) of epoxylignan compounds with α- glucosidase inhibitory activity

2018 ◽  
Vol 1 (T5) ◽  
pp. 110-115
Author(s):  
Tho Huu Le ◽  
Hai Xuan Nguyen ◽  
Mai Thi Thanh Nguyen
Keyword(s):  
Inhibitory Activity ◽  
Biological Activities ◽  
Stem Bark ◽  
Positive Control ◽  
Polyphenolic Compounds ◽  
Hydroxyl Group ◽  
Epoxy Ring ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Potent Inhibitory Activity

Epoxylignans are polyphenolic compounds, which possess various biological activities such as antiproliferative activity on cancer cells, antioxidant, antihyperglycemic,… In this research, we study on α- glucosidase inhibitory activity of 11 epoxylignans isolated from the stem of Artocarpus heterophyllus, the stem of Willughbeia cochinchinensis, the stem bark of Crateva religiosa, and the propolis of Trigona minor. The results showed that, compounds 1–4 and 7–10 were more potent inhibitory activity than that of positive control acarbose (IC50, 214.5 µM). Based on the results, their structure-activity relationships showed that the presence of the hydroxyl group at C-4, and C-4ʹ positions play an important role in increasing the activity. Furthermore, diepoxylignans having a ketone group at C-9′ exhibited stronger activity. In contrast, the opening of an epoxy ring at C-7 the C-9′ positions reduced the activity.

Structure-Activity Relationships for the Inhibition of Plasmin and Plasminogen Activation by Aromatic Diamidines and a Study of the Effect of Plasma Proteins on the Inhibition Process

1973 ◽  
Vol 29 (01) ◽  
pp. 154-167 ◽  
Author(s):  
J. D Geratz
Keyword(s):  
Serum Proteins ◽  
Relative Strength ◽  
Plasminogen Activation ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Absolute Strength ◽  
Inhibitory Spectrum ◽  
Human Plasminogen ◽  
Modifying Effect ◽  
The Absolute

Summary1. Structure-activity relationships for the inhibition of human plasmin were established for a large series of aromatic diamidines. The compounds are reversible competitive inhibitors and block the amidase and fibrinolytic activities of the enzym. The results confirm pentamidine (4,4’-diamidino α ω-diphenoxy-pentane) as the leading inhibitor (Ki = 3.3 (μM) and show distinct differences in the inhibitory spectrum of diamidines against plasmin as compared with trypsin, pancreatic kallikrein and thrombin.2. Diamidines are potent inhibitors of the SK-dependent activation of human plasminogen and of the activation of bovine plasminogen by the SK-human plasmin activator complex. Pentamidine is again the most powerful inhibitor of these systems.3. In fibrinolytic assays of plasmin and in plasminogen activation tests the relative strength of diamidines as compared with E-ACA is greatly influenced by the test conditions. The decisive factor is the presence in the incubation mixtures of lesser or greater amounts of plasma or serum proteins which bring about a fall in the absolute strength of diamidines and an increase in the absolute strength of E-ACA. In the fibrinolytic assay of plasmin, this modifying effect of added serum is based on a time- dependent interaction with the enzyme, thereby presumably altering its susceptibility to inhibition.

The Allylic Rearrangement of the Hydroxyl Group from C-9 to C-13 and the Absolute Configuration at C-9 of Leucomycin A3

1968 ◽  
Vol 16 (7) ◽  
pp. 1402-1404 ◽  
Author(s):  
SATOSHI OMURA ◽  
MICHIKO KATAGIRI ◽  
TOJU HATA ◽  
MIKIO HIRAMATSU ◽  
TERUTOSHI KIMURA ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Hydroxyl Group ◽  
Allylic Rearrangement ◽  
The Absolute

Structure-activity relationships of anti-tyrosinase and antioxidant activities of cinnamic acid and its derivatives

2021 ◽  
Author(s):  
Jianmin Chen ◽  
Mengnan Ran ◽  
Meixia Wang ◽  
Xinying Liu ◽  
Siwan Liu ◽  
...  
Keyword(s):  
Cinnamic Acid ◽  
Phenyl Ring ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Ic50 Value

Abstract The related structure-activity relationships (SARs) of cinnamic acid and its derivates have not been studied in details yet. Herein, anti-tyrosinase and antioxidant activities of 18 compounds were evaluated. The results demonstrated that the substituents on the phenyl ring of cinnamic acid led to the enhancement of the inhibition on monophenolase and the weakening of the inhibition on diphenolase. Among these tested compounds, 9 was firstly discovered as a tyrosinase inhibitor in a reversible competitive manner with IC50 value of 68.6 ± 4.2 μM. Docking results demonstrated 9 located into the catalytic center of tyrosinase. Antioxidant assay indicated that only one hydroxyl group on the phenyl ring was not enough to possess the radical scavenging activity, and the number of hydroxyl groups may be more important. This study will be helpful for development of new cinnamic acid derivates as tyrosinase inhibitors and antioxidants with higher efficacy.

Sign in / Sign up

Export Citation Format

Share Document