Galactosemic Cataractogenesis Disrupts Intracellular Interactions and Changes the Substrate Specificity of Choline/Ethanolamine Kinase

Lipids and the ocular lens

“…Changes in the synthesis of phospholipids and their precursors during cataractogenesis have been investigated, but further studies are necessary to determine if the changes are related to natural differences in phospholipid metabolism or if these alterations are the result of damageinduced pathways that lead to membrane repair ( 179 ). The concentrations and rates of synthesis of phosphorylcholine and phosphoethanolamine, precursors of phospholipid synthesis decrease in cataractogenesis and cataractogenic stress (180)(181)(182)(183)(184)(185)(186)(187)(188)(189)(190)(191), and the kinetic properties and substrate specifi city of choline/ethanolamine kinase change during galactosemic cataractogenesis ( 192 ). Increased phospholipid synthesis was reported to occur in an aldose-reductase inhibitor cataract model ( 185 ).…”

Safe use of genetically modified lactic acid bacteria in food. Bridging the gap between consumers, green groups, and industry

“…In traditional yoghurt fermentation, the undesirable sugar lactose is degraded only partially. One of the degradation products is galactose which may be harmful for people suffering from galactosemia and which also may cause cataract problems (Liu et al 1998). Vaughan describes the selection of spontaneous galactose-fermenting mutants of Streptococcus thermophilus, that contain up-mutations in the gal operon and that may assist in removal of undesired galactose from the food matrix (Vaughan et al 2001).…”

Effects of Cataractogenesis on the CDP-Choline Pathway: Changes in ATP Concentration and Phosphocholine Synthesis during and after Exposure of Rat Lenses to Sugars in vitro and in vivo

“…As previously described [21], male Harlan Sprague-Dawley weanling rats were fed either a 50% galactose diet to induce galactosemia or a control diet containing 50% starch (Bio Serve Inc., Frenchtown, N.J., USA). The rats were euthanized with CO 2 , and the lenses were carefully dissected from the eyes, cultured with [ 3 H]choline and analyzed as described below to study the effects of in vivo galactosemia on their [ATP] and on their ability to synthesize P-[ 3 H]Cho.…”

“…Previous studies [22] showed that the kinetic properties of choline/ethanolamine kinase in intact lenses differ from those in cell-free homogenates or purified preparations and that the kinetic properties of the enzyme(s) in intact galactosemic cataracts are intermediate between those of intact control lenses and lens homogenates [21]. Therefore, we studied P-Cho synthesis in cell-free homogenates (table 1) to determine whether the changes in P-Cho synthesis ( fig.…”

“…The concentrations and rates of synthesis of P-Cho and phosphoethanolamine decrease in cataractogenesis and cataractogenic stress [8][9][10][11][12][13][14][15][16][17][18][19][20]. Also, the apparent kinetic properties and substrate specificity of choline/ethanolamine kinase change during galactosemic cataractogenesis [21]. Knowledge of the changes in concentration and metabolism of phospholipid precursors, such as P-Cho, is necessary to understand the control of phospholipid synthesis and membrane repair in stressed, aging or cataractous lenses.…”