Incorporation of magnesium into rat dental enamel and its influence on crystallization

The incorporation of magnesium into the enamel of immature rats was studied by chemical analysis and X-ray diffraction. Magnesium solutions were injected subcutaneously and later intra-orally into growing rats. Increased magnesium was detected in the enamel at the late developmental stage, and a delay in enamel mineralization resulted from increased magnesium uptake. Incisal enamel from the Mg-injected rats had significant line-broadening on X-ray diffraction, characteristic of poorly crystallized enamel.

Incorporation of L-α-glycerophosphate and acyl-S-CoA into lipids by microsomes of Galleria mellonella

Microsomal preparations from the wax moth, Galleria mellonella, rapidly incorporated L-α-glycerophosphate and the acyl components of palmitoyl and stearoyl coenzyme A into glycerides. The rate of incorporation increased with pH at least up to pH 9.0 but so did enzyme inactivation; therefore a pH of 7.5 at 30 °C was adopted for the study.The incorporation of glycerophosphate did not proceed in the absence of added acyl-S-coenzyme A, but the amount of acylation required for the observed incorporation of glycerophosphate was of a greater order of magnitude than the amount of acyl-S-CoA added to the reaction mixture. It appears that the added acyl-S-CoA was acting as a positive effector for the release of endogenous acyl groups which also served as substrate for acylation.There was also evidence of an amount of endogenous acyl acceptor.The intervention of various amounts of endogenous substrates must confuse attempts to determine transacylase specificity by measuring relative rates of incorporation of exogenous substrates in microsomal preparations from the wax moth.