scholarly journals Crystal structure of norcoclaurine-6-O-methyltransferase, a key rate-limiting step in the synthesis of benzylisoquinoline alkaloids

2016 ◽  
Vol 87 (6) ◽  
pp. 641-653 ◽  
Author(s):  
Adeline Y. Robin ◽  
Cécile Giustini ◽  
Matthieu Graindorge ◽  
Michel Matringe ◽  
Renaud Dumas
Keyword(s):  
Crystal Structure ◽  
Benzylisoquinoline Alkaloids ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

scholarly journals Structural elucidation of the heterodimeric cis-prenyltransferase NgBR/DHDDS complex reveals novel insights in regulation of protein glycosylation

2020 ◽  
Author(s):  
Ban Edani ◽  
Kariona A. Grabińska ◽  
Rong Zhang ◽  
Eon Joo Park ◽  
Benjamin Siciliano ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Active Site ◽  
Protein Glycosylation ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Chain Synthesis ◽  
Rate Limiting ◽  
Activity Comparison ◽  
Long Chain ◽  
Resolution Structure

SummaryCis-prenyltransferase (cis-PTase) catalyzes the rate-limiting step in the synthesis of glycosyl carrier lipids required for protein glycosylation in the lumen of endoplasmic reticulum. Here we report the crystal structure of the human NgBR/DHDDS complex, which represents the first atomic resolution structure for any heterodimeric cis-PTase. The crystal structure sheds light on how NgBR stabilizes DHDDS through dimerization, participates in the enzyme’s active site through its C-terminal -RXG- motif, and how phospholipids markedly stimulate cis-PTase activity. Comparison of NgBR/DHDDS with homodimeric cis-PTase structures leads to a model where the elongating isoprene chain extends beyond the enzyme’s active site tunnel, and an insert within the α3 helix helps to stabilize this energetically unfavorable state to enable long chain synthesis to occur. These data provide unique insights into how heterodimeric cis-PTases have evolved from their ancestral, homodimeric forms to fulfill their function in long chain polyprenol synthesis.

scholarly journals Structural elucidation of thecis-prenyltransferase NgBR/DHDDS complex reveals insights in regulation of protein glycosylation

2020 ◽  
Vol 117 (34) ◽  
pp. 20794-20802 ◽  
Author(s):  
Ban H. Edani ◽  
Kariona A. Grabińska ◽  
Rong Zhang ◽  
Eon Joo Park ◽  
Benjamin Siciliano ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Active Site ◽  
Protein Glycosylation ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Chain Synthesis ◽  
Rate Limiting ◽  
Activity Comparison ◽  
Long Chain ◽  
Resolution Structure

Cis-prenyltransferase (cis-PTase) catalyzes the rate-limiting step in the synthesis of glycosyl carrier lipids required for protein glycosylation in the lumen of endoplasmic reticulum. Here, we report the crystal structure of the human NgBR/DHDDS complex, which represents an atomic resolution structure for any heterodimericcis-PTase. The crystal structure sheds light on how NgBR stabilizes DHDDS through dimerization, participates in the enzyme’s active site through its C-terminal -RXG- motif, and how phospholipids markedly stimulatecis-PTase activity. Comparison of NgBR/DHDDS with homodimericcis-PTase structures leads to a model where the elongating isoprene chain extends beyond the enzyme’s active site tunnel, and an insert within the α3 helix helps to stabilize this energetically unfavorable state to enable long-chain synthesis to occur. These data provide unique insights into how heterodimericcis-PTases have evolved from their ancestral, homodimeric forms to fulfill their function in long-chain polyprenol synthesis.

Ornithine Decarboxylase Activity in Cultured Endothelial Cells Stimulated by Serum, Thrombin and Serotonin

1978 ◽  
Vol 39 (02) ◽  
pp. 496-503 ◽  
Author(s):  
P A D’Amore ◽  
H B Hechtman ◽  
D Shepro
Keyword(s):  
Endothelial Cells ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Aortic Endothelial Cells ◽  
Ornithine Decarboxylase Activity ◽  
Rate Limiting Step ◽  
Bovine Aortic Endothelial Cells ◽  
Limiting Step ◽  
Rate Limiting ◽  
Serum Serotonin

SummaryOrnithine decarboxylase (ODC) activity, the rate-limiting step in the synthesis of polyamines, can be demonstrated in cultured, bovine, aortic endothelial cells (EC). Serum, serotonin and thrombin produce a rise in ODC activity. The serotonin-induced ODC activity is significantly blocked by imipramine (10-5 M) or Lilly 11 0140 (10-6M). Preincubation of EC with these blockers together almost completely depresses the 5-HT-stimulated ODC activity. These observations suggest a manner by which platelets may maintain EC structural and metabolic soundness.

Dynamics of hepatic and peripheral insulin effects suggest common rate-limiting step in vivo

Diabetes ◽  
1993 ◽  
Vol 42 (2) ◽  
pp. 296-306 ◽  
Author(s):  
D. C. Bradley ◽  
R. A. Poulin ◽  
R. N. Bergman
Keyword(s):  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

Kinetics of cyclization of S-ethoxycarbonylmethylisothiouronium chloride to 2-imino-4-thiazolidone

1979 ◽  
Vol 44 (3) ◽  
pp. 912-917 ◽  
Author(s):  
Vladimír Macháček ◽  
Said A. El-bahai ◽  
Vojeslav Štěrba
Keyword(s):  
Hydrochloric Acid ◽  
Dilute Hydrochloric Acid ◽  
Base Catalysis ◽  
General Base ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Kinetics Of Formation ◽  
Acid Catalyzed ◽  
Rate Limiting ◽  
Kinetics Of

Kinetics of formation of 2-imino-4-thiazolidone from S-ethoxycarbonylmethylisothiouronium chloride has been studied in aqueous buffers and dilute hydrochloric acid. The reaction is subject to general base catalysis, the β value being 0.65. Its rate limiting step consists in acid-catalyzed splitting off of ethoxide ion from dipolar tetrahedral intermediate. At pH < 2 formation of this intermediate becomes rate-limiting; rate constant of its formation is 2 . 104 s-1.

Sign in / Sign up

Export Citation Format

Share Document