Synthesis and application of the methyl analogues of S-adenosyl-L-methionine / 生物工程学报

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.

Efficient synthesis of L-methionine by engineering the one carbon module of Escherichia coli / 生物工程学报

L-methionine, also known as L-aminomethane, is one of the eight essential amino acids required by the human body and has important applications in the fields of feed, medicine, and food. In this study, an L-methionine high-yielding strain was constructed using a modular metabolic engineering strategy based on the M2 strain (Escherichia coli W3110 ΔIJAHFEBC/PAM) previously constructed in our laboratory. Firstly, the production of one-carbon module methyl donors was enhanced by overexpression of methylenetetrahydrofolate reductase (methylenetetrahydrofolate reductase, MetF) and screening of hydroxymethyltransferase (GlyA) from different sources, optimizing the one-carbon module. Subsequently, cysteamine lyase (hydroxymethyltransferase, MalY) and cysteine internal transporter gene (fliY) were overexpressed to improve the supply of L-homocysteine and L-cysteine, two precursors of the one-carbon module. The production of L-methionine in shake flask fermentation was increased from 2.8 g/L to 4.05 g/L, and up to 18.26 g/L in a 5 L fermenter. The results indicate that the one carbon module has a significant impact on the biosynthesis of L-methionine, and efficient biosynthesis of L-methionine can be achieved through optimizing the one carbon module. This study may facilitate further improvement of microbial fermentation production of L-methionine.

Microbial production of S-adenosyl-l-methionine: a review / 生物工程学报

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.

Effect of Enhancers on in vitro and in vivo Skin Permeation and Deposition of S-Methyl-(L)-Methionine

S-methyl-(L)-methionine (SMM), also known as vitamin U, is commercially available as skin care cosmetic products for its wound healing and photoprotective effects. However, the low skin permeation expected of SMM due to its hydrophilic nature with a log P value of −3.3, has not been thoroughly addressed. The purpose of this study thus was to evaluate the effect of skin permeation enhancers on the skin permeation/deposition of SMM. Among the enhancers tested for the in vitro skin permeation and deposition of SMM, oleic acid showed the most significant enhancing effect. Moreover, the combination of oleic acid and ethanol further enhanced in vitro permeation and deposition of SMM through hairless mouse skin. Furthermore, the combination of oleic acid and ethanol significantly increased the in vivo deposition of SMM in the epidermis/dermis for 12 hr, which was high enough to exert a therapeutic effect. Therefore, based on the in vitro and in vivo studies, the combination of oleic acid and ethanol was shown to be effective in improving the topical skin delivery of SMM, which may be applied in the cosmetic production process for SMM.

Clinical Study of S-Adenosyl-L-Methionine Combined with Ursodeoxycholic Acid in Treatment of 40 Cases with Intrahepatic Cholestasis of Pregnancy / 医药导报

Objective To observe the clinical effects and the safety of S-adenosy-L-methionine ( SAMe ) associated with ursodeoxycholic acid (UDCA) in treating intrahepatic cholestasis of pregnancy (ICP). Methods Eighty patients with ICP were randomly divided into treatment group ( treated with UDCA orally, 250 mg, TID and simultaneously with intravenous SAMe 1. 0 g, qd) and control group (treated with intravenous SAMe 1. 0 g, qd). Pruritus degree, serum total bilirubin (TB), total bile acid (TBA), glycocholic acid (CG), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were analyzed before and after the treatment, and the pregnancy outcomes, such as the rate of premature, uterine-incision delivery and fetal distress were recorded. Results After treatment, the pruritus degree and the levels of TB, TBA, CG, ALT AST were decreased significantly compared with pretreatment in both groups. TB, TBA, AST and ALT of the treatment group decreased from (27.83±9. 34), (45. 62±18. 30) μmol·L-1, (195. 98±30. 22), (188. 69±29. 11) U·L-1 to (11. 81±4. 91), (11. 88±2. 23) μmol·L-1, (73. 59±21. 53), (67. 94±30. 53) U·L-1, respectively, and TB, TBA, AST, ALT of the control group decreased from (27. 49±7. 87), (49. 12±10. 39) μmol·L-1, (211. 93±34. 9), (210. 40±43. 39) U·L-1 to (16. 08± 6.23), (23.88±6.63) μmol·L-1, (87. 20±32. 52), (81. 77±35. 16) U·L-1, respectively (P0. 05), but the declines of TB, TBA and CG in treatment group were superior to those of the control group (P<0. 05). Conclusion In terms of improving pruritus, liver function and pregnancy outcome, single SAMe application could obtain similar effects compared with SAMe combined with UDCA, but SAMe combined with UDCA is more effective than the single SAMe application in decreasing the level of TBA and CG.

Ameliorative Effect of a Selective Endothelin ETA Receptor Antagonist in Rat Model of L-Methionine-induced Vascular Dementia

The present study was designed to investigate the efficacy of selective ET(A) receptor antagonist, ambrisentan on hyperhomocysteinemia-induced experimental vascular dementia. L-methionine was administered for 8 weeks to induce hyperhomocysteinemia and associated vascular dementia in male rats. Ambrisentan was administered to L-methionine-treated effect rats for 4 weeks (starting from 5th to 8th week of L-methionine treatment). On 52nd day onward, the animals were exposed to the Morris water maze (MWM) for testing their learning and memory abilities. Vascular endothelial function, serum nitrite/nitrate levels, brain thiobarbituric acid reactive species (TBARS), brain reduced glutathione (GSH) levels, and brain acetylcholinesterase (AChE) activity were also measured. L-methionine-treated animals showed significant learning and memory impairment, endothelial dysfunction, decrease in/serum nitrite/nitrate and brain GSH levels along with an increase in brain TBARS levels and AChE activity. Ambrisentan significantly improved hyperhomocysteinemia-induced impairment of learning, memory, endothelial dysfunction, and changes in various biochemical parameters. These effects were comparable to that of donepezil serving as positive control. It is concluded that ambrisentan, a selective ET(A) receptor antagonist may be considered as a potential pharmacological agent for the management of hyperhomocysteinemia-induced vascular dementia.

The efficacy of S-adenosy-L-methionine(SAMe) combided with LMWH in the treatment of intrahepatic cholestasis of pregnancy / 中国基层医药

Objective To investigate the efficacy of S-adenosy-L-methionine (SAMe) combided with LMWH in the treatment of intrahepatic cholestasis of pregnancy. Methods 47 patients with intrahepatic cholestasis of pregnancy were divided into two groups:A group(n = 21)received a combination of SAMe and LMWH,B group(n = 26)received only SAMe.The symptom of itching and serum biochemical indexes,including TBA,TB,ALT,and AST were observed after 7days,and the pregnancy outcome between the two groups were compared after delivery. Results All the patients had a significant improvement in pruritus and TBA,TB,ALT,and AST(P ＜0.01＝.After 7 days,there were significant differences in prurits,FBA,AST,ALT,in receiving combination of SAMe and LMWH comparing with received SAMe alone(P ＜0.05＝.The incidence of amniotic fluid pollution was significantly different between the two groups(P＜0.01＝. Conclusion In women with intrahepatic cholestasis of pregnancy,combination of SAMe and LMWH were safe and efficient in the near future.

Detection of S-Adenosyl-L-methionine in Fermentation Liquid by HPLC-UV / 中国生物工程杂志

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.

Clinical Evaluation of S-Adenosyl-L-Methionine in Treatment of Jaundice in 202 Newborn Infants / 实用儿科临床杂志

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.

High expression of the L-Methionine ?-lyase gene in E. coli / 医学研究生学报

Objective: To identify and highly express the L-Methionine ?-lyase gene from Trichomonas vaginalis(TVMGL).Methods: The TVMGL gene was cloned into pGEX 4T-2,the recombinant protein expressed in E.coli DH5?and confirmed by SDS-PAGE.Results: Denaturing SDS-PAGE analysis confirmed the predicted size of the fusion protein(GST-TVMGL,68 000) and showed high purity after subsequent affinity chromatography on Glutathione sepharose 4B.The target proteins amounted to 34% of the total bacteria proteins.Conclusion: The L-Methionine ?-lyase gene was highly expressed in E.coli.

Cloning of L-Methionine ?-lyase gene / 医学研究生学报

Objective:To identify,clone,sequence the L-Methionine ?-lyase gene from Trichomonas vaginalis(TVMGL1).Methods:Total RNA was prepared from primitive protozoon trichomonas vaginalis,cDNA fragment encoding Methionine ?-lyase gene was amplified by RT-PCR using specific primers,and then was cloned into pGEM-T vector.Inserted Methionine ?-lyase gene was sequenced by ABI 3730 DNA Sequencer.Results:Analysis indicates that the DNA fragment is 1 191 base pairs in length and has high nucleotide homology with that reported previously.Conclusion:L-Methionine ?-lyase gene was successfully cloned.

The study of genome DNA methylation in rheumatoid arthritis / 中华风湿病学杂志

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.

Optimal Study on the Fermentation Conditions of S-adenosyl-L-methionine / 微生物学通报

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.