Borek said:What is alpha carbon in other cases?
Borek said:What makes this carbon 'alpha'? Why is it called this way? How does it differ from 'beta'?
soopo said:The LHS molecule is alpha-keto acid, while RHS is beta-keto acid in the following picture.
http://dl.getdropbox.com/u/175564/alpha-beta-acids.png
Borek said:If you were looking for the answer in wikipedia, it would be better to start at the very beginning:
http://en.wikipedia.org/wiki/Alpha_carbon
Borek said:OK now.
As you see concept of 'alpha'. 'beta' and 'gamma' carbons is widely used in chemistry. Not very formal, often very useful.
soopo said:It seems that the same naming convention does not apply here.
Ygggdrasil said:The alpha and beta conventions for sugars is completely different from the alpha, beta, gamma, etc. nomenclature that you were discussing previously.
For cyclic sugars, alpha refers to a cyclized sugar in which the OH group of the anomeric carbon (the carbon with two bonds to oxygen) is on the opposite side of the ring as the alkyl group on the ring.
Alpha-keto acid and keto acid are both types of organic compounds that contain a carbonyl group (-C=O). However, the difference lies in the position of this group on the carbon chain. In alpha-keto acids, the carbonyl group is attached to the carbon atom next to the carboxyl group (-COOH), while in keto acids, the carbonyl group is attached to any other carbon atom on the chain.
Some examples of alpha-keto acids include pyruvic acid, which is a key intermediate in cellular respiration, and alpha-ketoglutaric acid, which is involved in the citric acid cycle. Examples of keto acids include acetoacetic acid, which is produced during ketosis, and phenylpyruvic acid, which is a byproduct of phenylalanine metabolism.
Due to the position of the carbonyl group, alpha-keto acids tend to be more reactive than keto acids. This is because the proximity of the carbonyl group to the carboxyl group allows for easier formation of enol forms, which are more reactive than keto forms. Additionally, alpha-keto acids are more acidic than keto acids due to the presence of the carboxyl group.
Both alpha-keto acids and keto acids play important roles in various biological processes. For example, alpha-ketoglutaric acid is involved in amino acid metabolism, while acetoacetic acid is a source of energy during periods of fasting or low carbohydrate intake. Additionally, some keto acids, such as oxaloacetic acid, act as intermediates in metabolic pathways.
Yes, alpha-keto acids can be converted into keto acids through a process called keto-enol tautomerism. In this process, the carbonyl group in the alpha-keto acid shifts to a different position on the carbon chain, creating a keto acid. However, this conversion is reversible and can occur multiple times, depending on the conditions of the reaction.