Possible Interaction: Alanine and Homocysteine

“Competition studies revealed that the small neutral amino acids tyrosine, cysteine, glycine, serine, alanine , methionine, and leucine inhibited Hcy uptake in both cell types, but the inhibition was greater for tyrosine, serine, glycine, and alanine in HAECs.”

“ Homocysteine also dose-dependently inhibited insulinotropic responses to a range of glucose-dependent secretagogues including nutrients ( alanine , arginine, 2-ketoisocaproate), hormones (glucagon-like peptide-1 (7-36)amide, gastric inhibitory polypeptide and cholecystokinin-8), neurotransmitter (carbachol), drug (tolbutamide) as well as a depolarising concentration of KCl or elevated Ca2+.”

“The transport of cystine was Na+ dependent and decreased in the presence of N-ethylmaleimide, and it was competitively inhibited by DL-homocystine and L-alanine.”

“Insulinotropic responses to alanine , arginine, 2-ketoisocaproate, elevated Ca2+, tolbutamide, potassium chloride (KCl), forskolin, and phorbol 12-myristate 13-acetate were also significantly reduced by homocysteine.”

“Insulin secretory responses to alanine were inhibited by homocysteine , homocysteine thiolactone, homocysteic acid and cysteic acid.”

“Supplementation of the culture medium with alanine gave partial relief from the inhibitory effects of Hcy.”