叶酸与蛋白质合成

叶酸作为一碳单位携带分子,在机体内发挥着非常重要的作用,它所参与的甲基化作用与蛋白质的合成紧密相关,本文对叶酸影响蛋白质的合成过程做了比较全面的综述,旨在阐明叶酸在蛋白质合成各个阶段中的作用。     

Folic acid biosensors: A review

Folic acid (FA) also known as (N-[p-{[(2-amino-4-hydroxy-6-pteridinyl) methyl] amino} benzoyl]-l-glutamic acid), is a water soluble vitamin found in plants and animals. The deficiency of FA leads to an increased risk of various diseases like neural tube defects in newborn, cardiovascular disease, cancer, Alzheimer’s disease and megaloblastic anemia. The normal levels of FA in human blood serum should fall in the range between 2 and 15 ng/mL. Present review article discusses the classification, principles, advantages and disadvantages of FA biosensing methods. FA biosensors operate within 3–300 s, in pH range, 1.8–7.8, concentration range 8.71 × 10⁻⁹ μM for FA. The FA biosensors displayed detection limits (LOD) between 1.6 × 10⁻¹¹ to 0.091 μM and with working potential −0.88 to 4.5 V. These biosensors measured FA level in various biological and pharmaceuticals samples.     

Folic acid and primary prevention of birth defects

Birth defects (BDs) are an important public health problem, due to their overall incidence, occurring in 2-3% of live births in European Union. Neural tube defects (NTDs) are among major NTDs, due to their severity and relatively high incidence; in the meanwhile NTDs are also the most effectively preventable BDs to date. In particular, an adequate folic acid (FA) intake reduces both the occurrence and the recurrence of NTDs; FA is the synthetic form of folates, naturally occurring vitamins in a number of foods, especially vegetables. The daily intake of 0.4 mg of FA should be recommended to all women of childbearing age who plan to become pregnant. The Italian Network for Primary Prevention of BDs through FA Promotion has achieved a significant improvement in FA awareness and use in the periconceptional period. Nevertheless, primary prevention of BDs needs to make further progress; the Italian National Centre for Rare Diseases participates in european sureveillance of congenital anomalies (EUROCAT) Joint Action as coordinator of activities on the effectiveness of BDs prevention. Mandatory food fortification with FA has not been introduced in any European country. The health benefits of FA in reducing the risk of NTDs are undisputed; however mechanistic and animal studies suggest a relationship between high FA intakes and increased cancer promotion, while human studies are still inconsistent and inconclusive. A Working Group organized by the European Food Safety Authority pointed out significant uncertainties about fortification safety and the need for more studies; currently, FA intake from fortified foods and supplements should not exceed 1 mg/day in adults. In conclusion, based on up-to-date scientific evidence, the Italian Network strategy pivots on periconceptional supplementation integrated with promotion of healthy eating habits, support to health education, enhancing the role of women in managing life choices about their health and pregnancy and increasing the scientific knowledge about BDs primary prevention.     

Folic acid and pteroylpolyglutamate contents of archaebacteria.

Cell extracts of methanogens and the thermoacidophile Sulfolobus solfataricus contained little or no folic acid (pteroylglutamate) or pteroylpolyglutamate activity (less than 0.1 nmol/g [dry weight]). However, the halophile Halobacterium salinarum contained pteroylmono- or pteroyldiglutamates, and Halobacterium volcanii and Halobacterium halobium contained pteroyltriglutamates at levels equivalent to those in eubacteria (greater than 1 nmol/g [dry weight]).