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J Ladik

Publications and source records attributed to J Ladik.

32 records · Page 2Linked to original sources
PubMed1979

Quantum chemical calculations of model systems for ascorbic acid adducts with Schiff bases of lysine side chains: possibility of internal charge transfer in proteins.

Ab initio self-consistent field calculations for neutral and cationic ascorbic acid and model compounds have been performed. Furthermore, the bicyclic addition products of alpha-hydroxytetronic acid with methylglyoxal and with the Schiff base formed between methylglyoxal and methylamine have been calculated, again in their neutral and cationic forms, respectively. The results indicate that the investigated cations can act as strong electron acceptors. With the help of space-filling molecular models it has been demonstrated that such conformations of the Schiff base formed between the primary amino group of lysine side chains in proteins and the ascorbic acid methylglyoxal acetal are possible in which the lactone carbonyl group comes near to the N atoms of the peptide groups, so that charge can be transferred between these subunits.

Ascorbic Acid↗
PubMed1978

Internal charge transfer in proteins to the Schiff bases of their lysine side chains.

Stereochemical investigations carried out with the aid of molecular models show that the Schiff bases formed between methylglyoxal and the primary amino groups of the lysine side chains of proteins can bend back in such a way to the N atoms of the peptide groups that a charge transfer can occur between these groups and the oxygen atoms of the Schiff bases. Ab initio molecular orbital calculations support this finding.

Journal Article↗