scholarly journals An early intermediate in the biosynthesis of biotin: Incorporation studies with [1,7-14C2]pimelic acid

1966 ◽  
Vol 101 (3) ◽  
pp. 601-606 ◽  
Author(s):  
M A Eisenberg ◽  
R Maseda
Keyword(s):  
Penicillium Chrysogenum ◽  
Pimelic Acid ◽  
Culture Filtrates ◽  
High Yields ◽  
Intermediate Role

1. An unknown biotin vitamer was obtained in high yields in culture filtrates of Penicillium chrysogenum. 2. Production of this vitamer and desthiobiotin is controlled by the biotin concentration in the medium. 3. The unknown vitamer becomes labelled when the organism is grown in the presence of radioactive pimelic acid. 4. Chromatographic procedures were developed for the purification of the radioactive vitamer. 5. The vitamer is extremely stable in concentrated acid but gives rise to new vitamers under certain conditions. 6. The intermediate role of this vitamer in the synthesis of biotin is discussed.

scholarly journals The biosynthesis of biotin in growing yeast cells: The formation of biotin from an early intermediate

1966 ◽  
Vol 101 (3) ◽  
pp. 598-600 ◽  
Author(s):  
M A Eisenberg
Keyword(s):  
Biological Activity ◽  
Penicillium Chrysogenum ◽  
Previous Investigation ◽  
Specific Activity ◽  
Yeast Cells ◽  
Pimelic Acid ◽  
Avidin Biotin Complex

1. Yeast cells grown in the presence of an unknown radioactive biotin vitamer produced by Penicillium chrysogenum incorporated the vitamer into the newly synthesized biotin. 2. The biotin was isolated as the avidin-biotin complex and after hydrolysis the biological activity and radioactivity were shown to be coincidental. 3. The specific activity of the biotin was identical with that of the pimelic acid used in a previous investigation to label the unknown vitamer. 4. The role of the unknown biotin vitamer as an intermediate in biotin biosynthesis is discussed.

Synthetic and Mechanistic Studies of a Versatile Heteroaryl Thioether Directing Group for Pd(II) Catalysis

2019 ◽  
Author(s):  
Andrew Romine ◽  
Kin Yang ◽  
Malkanthi Karunananda ◽  
Jason Chen ◽  
Keary Engle
Keyword(s):  
Mechanistic Studies ◽  
Salvianolic Acid ◽  
Wide Range ◽  
Computational Data ◽  
Synthetic Utility ◽  
Directing Group ◽  
High Yields ◽  
Julia Olefination ◽  
Reaction Progress Kinetic Analysis

A weakly coordinating monodentate heteroaryl thioether directing group has been developed for use in Pd(II) catalysis to orchestrate key elementary steps in the catalytic cycle that require conformational flexibility in a manner that is difficult to accomplish with traditional strongly coordinating directing groups. This benzothiazole thioether, (BT)S, directing group can be used to promote oxidative Heck reactivity of internal alkenes providing a wide range of products in moderate to high yields. To demonstrate the broad applicability of this directing group, arene C–H olefination was also successfully developed. Reaction progress kinetic analysis provides insights into the role of the directing group in each reaction, which is supplemented with computational data for the oxidative Heck reaction. Furthermore, this (BT)S directing group can be transformed into a number of synthetically useful functional groups, including a sulfone for Julia olefination, allowing it to serve as a “masked olefin” directing group in synthetic planning. In order to demonstrate this synthetic utility, natural products (+)-salvianolic acid A and salvianolic acid F are formally synthesized using the (BT)S directed C–H olefination as the key step.

Phytocenotic selection of perennial grasses as a factor of increasing the productivity of mixed agrophytocenoses

2020 ◽  
Author(s):  
V.N. Zolotarev ◽  
◽  
I.S. Ivanov ◽  
O.N. Lyubtseva
Keyword(s):  
Perennial Grasses ◽  
New Varieties ◽  
The Creation ◽  
High Yields ◽  
Selection Of

Based on the analysis of data available in the literature and our own experimental material on phytocenotic selection of the stony stalk (Bromopsis inermis Holub.) the important role of competition between plants in the field for the creation of new varieties of perennial grasses that provide high yields of feed polyvid agrophytocenoses is shown.

The intermediate role of 18-hydroxycorticosteroids in aldosterone biosynthesis

1968 ◽  
Vol 24 (12) ◽  
pp. 1199-1201 ◽  
Author(s):  
P. Vecsei ◽  
D. Lommer ◽  
H. P. Wolff
Keyword(s):  
Intermediate Role

Role of toxins in etiology of root rot disease of wheat

1977 ◽  
Vol 55 (13) ◽  
pp. 1801-1806 ◽  
Author(s):  
Ross B. Pringle
Keyword(s):  
Root Rot ◽  
Toxic Substance ◽  
Toxic Metabolite ◽  
Root Rot Disease ◽  
Culture Filtrates ◽  
Helminthosporium Sativum ◽  
Rot Disease

Although no host-specific toxin, nor a great quantity of any toxic substance, has been found in culture filtrates of 26 different isolates of Helminthosporium sativum, the amount of the toxic metabolite, victoxinine, produced by these strains, may be correlated generally to their aggressiveness towards wheat.

Intermediate role of α-keto acids in the formation of Strecker aldehydes

2013 ◽  
Vol 141 (2) ◽  
pp. 1140-1146 ◽  
Author(s):  
Francisco J. Hidalgo ◽  
Rosa M. Delgado ◽  
Rosario Zamora
Keyword(s):  
Keto Acids ◽  
Strecker Aldehydes ◽  
Intermediate Role
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