51529-24-9Relevant academic research and scientific papers
Polymerization degree of oligomethionine to determine its bioavailability when added to a low-protein diets
Kasai, Takanori,Tanaka, Tomoyuki,Kiriyama, Shuhachi
, p. 828 - 834 (2007/10/03)
Oligo-L-methionine ethylester (OMOEt) prepared by the papain- catalyzed oligomerization of L-methionine ethylester (MetOEt) is a mixture of pentamer to dodecamer and has nearly the same supplementary effect as free methionine (Met) for the growth of rats when added to a low casein diet, but its supplementary effect to a low-soy protein isolate (sPI) diet is not consistent and depends on the degree of polymerization. Rats were fed for 2wk with an 8% casein or 10% SPI diet supplemented with 0.3% L- Met, each chemically synthesized Met(n)OEt with a polymerization degree (n) of 6, 7, 8, or 9, or with OMOEt prepared by papain-catalyzed polymerization of MetOEt. Met6OEt, Met7OEt, and Met8OEt had nearly the same supplementary effect on the growth of rats, as did free Met, both with the 8% casein and 10% SPI diets. The supplementary effect of Met9OEt was not significantly lower than that of Met when added to the 8% casein diet, but was significantly lower when added to the 10% SPI diet. The digestibility of Met9OEt supplemented to the 8% casein and 10% SPI diets was 50.5% and 35.6%, respectively. It appears likely that there is a gap in the bioavailability of oligomethionine between the octamer and nonamer when added to a low-protein diet, probably due to the rigidity of the structure increasing with the polymerization degree by α-helix formation. Although the differences in absorption rate of Met from OMOEt for a short time after feeding has been related to the different effects of supplemented OMOEt, the absorption rate of OMOEt for 30 min after feeding was not considered to be the main cause of the differential effects of OMOEt in this experiment.
FORMATION CONSTANTS OF SILVER(I) COMPLEXES OF SOME SULPHUR-CONTAINING DIPEPTIDES AND VALYLVALINE
Lyons, Anthony Q.,Pettit, Leslie D.
, p. 2305 - 2308 (2007/10/02)
Formation constants at 25 deg C and l = 0.10 mol dm-3 (KNO3) have been determined for the complexes of AgI with a range of nine dipeptides which incorporate side-chains containing one (glycylmethionine and methionylglycine) or two sulphur donor atoms.In the latter case dipeptides formed from amino acids of the same and of different chiralities were studied (e.g.L-methionyl-L-methionine and L-methionyl-D-methionine).The results are compared with those for valylvaline.Values for the formation constants are interpreted in terms of the preferred conformations of the dipeptides, and the tendency for AgI to bond to S-donor atoms or to adopt linear co-ordination through the formation of dimeric complexes.
