ABSTRACT
S-adenosyl-l-methionine (SAM) is ubiquitous in living organisms and plays important roles in transmethylation, transsulfuration and transamination in organisms. Due to its important physiological functions, production of SAM has attracted increasing attentions. Currently, researches on SAM production mainly focus on microbial fermentation, which is more cost-effective than that of the chemical synthesis and the enzyme catalysis, thus easier to achieve commercial production. With the rapid growth in SAM demand, interests in improving SAM production by developing SAM hyper-producing microorganisms aroused. The main strategies for improving SAM productivity of microorganisms include conventional breeding and metabolic engineering. This review summarizes the recent research progress in improving microbial SAM productivity to facilitate further improving SAM productivity. The bottlenecks in SAM biosynthesis and the solutions were also addressed.
Subject(s)
S-Adenosylmethionine/metabolism , Plant Breeding , Fermentation , Metabolic EngineeringABSTRACT
Methylation plays a vital role in biological systems. SAM (S-adenosyl-L-methionine), an abundant cofactor in life, acts as a methyl donor in most biological methylation reactions. SAM-dependent methyltransferases (MTase) transfer a methyl group from SAM to substrates, thereby altering their physicochemical properties or biological activities. In recent years, many SAM analogues with alternative methyl substituents have been synthesized and applied to methyltransferases that specifically transfer different groups to the substrates. These include functional groups for labeling experiments and novel alkyl modifications. This review summarizes the recent progress in the synthesis and application of SAM methyl analogues and prospects for future research directions in this field.
Subject(s)
S-Adenosylmethionine/metabolism , Methionine , Methyltransferases/metabolism , Methylation , RacemethionineABSTRACT
A method for the determination of S-Adenosyl-L-methionine in fermentation liquid using the high performance liquid chromatography coupled with UV detector (HPLC-UV) was developed.A good linearity was obtained in the range of 0.1～1.0g/L (r = 0.9969) for S-Adenosyl-L-methionine.The average recoveries of S-Adenosyl-L-methionine were 99.89%～101.7% and the relative standard deviations were 0.48%～1.36%.The method is simple and rapid with reproducibility for the determination of S-Adenosyl-L-methionine in ferment liquid.
ABSTRACT
Objective To observe the effect of S-adenosyl-L-methionine(SAMe) in treatment of jaundice in newborns and its mechanism.Methods Two hundred and two newborn infants with jaundice were treated with SAMe,76 cases in control group treated with phototherapy and liver enzyme induction elixir;SAMe 30-60 mg/(kg?d) were added to 202 cases intravenously in treatment group.The total biliorubin(T-BILI),direct bilinrubin(D-BILI) and indirect bilinrubin(I-BILI) were dynamically detected.Results Six days after treatment,the skin jaundice index in treatment group decreased remarkably.T-BILI,D-BILI and I-BILI decreased significantly.The curing effectiveness was higher in treatment group than that in control group.The number of applicating blood products and albumin,and blood produets/albumin were decreased in treatment group than those in control group.In those who used glucose to dissolve the SAMe 2.68% had blood-vessel phlebitis.Conclusions SAMe can efficiently quicken the retrogression of jaundice in newborns.It can reduce the use of blood products.It is a reliable and safe drug to treat jaundice in newborns.
ABSTRACT
Objective To study the genome DNA methylation in rheumatoid arthirits(RA)and the re- lated factors of DNA methylation.Methods Twenty-first cases with RA and 20 controls were recruited to par- ticipate the study.Plasma Hcy,SAM,SAH,the MTHFR gene C677T polymorphism and the expression of LFA-1 in CD4~+T cells was measured in all patients and controls.Results①The SAM levels were lower sig- nificantly in RA groups than in controls.The SAH levels were higher significantly in RA groups than in con- trols.②There was significant inverse correlation between plasma Hcy level and SAM level(r=-0.932,P＜0.01). There was significant positive correlation between plasma Hcy level and SAH level(r=0.924,P＜0.01).③The expression of LFA-1 in CD4~+T cells was higher significantly in RA groups than in controls.There was a signif- icant positive correlation between LFA-1 expression level and Hcy level(r=0.557,P＜0.01),a significant in- verse correlation between LFA-1 expression level and SAM level(r=-0.651,P＜0.01).④The MTHFR gene mu- tation lead to dramatically increase of Hcy,SAH level and the expression of LFA-1 level in CD4~+T cells and genome DNA hypomethylation.Conclusion①Hypomethylation of genome DNA is found in most RA pa- tients.②The factors associated with genome DNA hypomethylation include MTHFR gene mutation and hyper- homocysteinemia.③The expression of LFA-1 in CD4~+ T cells is higer in RA groups than in controls,which re- lates to the DNA methylation level and the MTHFR gene C677T polymorphism.
ABSTRACT
This paper focuses mainly on the study of optimal fermentation conditions of S-adenosyl-L-methionine.Effects of carbon sources,nitrogen sources,inorganic constituents,growth factors and adding time of L-methionine on the yield,the content and biomass of S-adenosyl-L-methionine are studied.And ingredients of the culture medium are also optimized by the method of uniform design.The final optimum culture medium contains: glucose 30 g,Yeast powder 11 g,(NH_4)_2SO_4 12 g,K_2HPO_4?3H_2O 5 g,KH_2PO_4 10 g,MnSO_4?H_2O 0.09 g,ZnSO_4?7H_2O 0.14 g,MgCl_20.5 g,CaCl_2 0.3 g,CuSO_4 0.005 g per liter. Using that optimum culture medium,the yield of S-adenosyl-L-methionine can reach 0.9 g/L in Erlenmeyer flask which is 30 % higher than before.Experiment on 5 L fermenter reveals that the accumulation of S-adenosyl-L-methionine can reach 2.66 g/L.Biomass is 23.4 g/L.