Problems in the determination of the specific radioactivity of uniformly 14C-labelled amino-acids after their reaction with ninhydrin

The Analyst ◽  
1975 ◽  
Vol 100 (1191) ◽  
pp. 369 ◽  
Author(s):  
R. Bishop ◽  
A. P. Sims
Keyword(s):  
Amino Acids ◽  
Specific Radioactivity

scholarly journals Pentose cycle and reducing equivalents in rat mammary-gland slices

1972 ◽  
Vol 128 (4) ◽  
pp. 879-899 ◽  
Author(s):  
Joseph Katz ◽  
P. A. Wals
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Specific Radioactivity ◽  
Acid Synthesis ◽  
Glucose Carbon ◽  
Rat Mammary Gland ◽  
Reducing Equivalents

1. Slices of mammary gland of lactating rats were incubated with glucose labelled uniformly with 14C and in positions 1, 2, 3 and 6, and with 3H in all six positions. Glucose carbon atoms are incorporated into CO2, fatty acids, lipid glycerol, the glucose and galactose moieties of lactose, lactate, soluble amino acids and proteins. C-3 of glucose appears in fatty acids. The incorporation of 3H into fatty acids is greatest from [3-3H]glucose. 3H from [5-3H]glucose appears, apart from in lactose, nearly all in water. 2. The specific radioactivity of the galactose moiety of lactose from [1-14C]- and [6-14C]-glucose was less, and that from [2-14C]- and [3-14C]-glucose more, than that of the glucose moiety. There was no randomization of carbon atoms in the glucose moiety, but it was extensive in galactose. 3. The pentose cycle was calculated from 14C yields in CO2 and fatty acids, and from the degradation of galactose from [2-14C]glucose. A method for the quantitative determination of the contribution of the pentose cycle, from incorporation into fatty acids from [3-14C]glucose, is derived. The rate of the reaction catalysed by hexose 6-phosphate isomerase was calculated from the randomization pattern in galactose. 4. Of the utilized glucose, 10–20% is converted into lactose, 20–30% is metabolized via the pentose cycle and the rest is metabolized via the Embden–Meyerhof pathway. About 10–15% of the triose phosphates and pyruvate is derived via the pentose cycle. 5. The pentose cycle is sufficient to provide 80–100% of the NADPH requirement for fatty acid synthesis. 6. The formation of reducing equivalents in the cytoplasm exceeds that required for reductive biosynthesis. About half of the cytoplasmic reducing equivalents are probably transferred into mitochondria. 7. In the Appendix a concise derivation of the randomization of C-1, C-2 and C-3 as a function of the pentose cycle is described.

scholarly journals Rapid Organocatalytic Chirality Analysis of Amines, Amino Acids, Alcohols, Amino Alcohols and Diols with Achiral Iso(thio)cyanate Probes

2021 ◽  
Author(s):  
Eryn Nelson ◽  
Jeffrey S. S. K. Formen ◽  
Christian Wolf
Keyword(s):  
Amino Acids ◽  
Absolute Configuration ◽  
Rapid Determination ◽  
Amino Alcohols ◽  
Enantioselective Synthesis ◽  
Widespread Occurrence ◽  
Chiral Compounds ◽  
New Methods ◽  
The Absolute

The widespread occurrence and significance of chiral compounds does not only require new methods for their enantioselective synthesis but also efficient tools that allow rapid determination of the absolute configuration,...

Sign in / Sign up

Export Citation Format

Share Document