The interconversion of serine and glycine: role of pteroylglutamic acid and other cofactors

A New Stable Bicarbonate Dialysis Solution for Peritoneal Dialysis: Preliminary Report

This paper describes the use of glycylglycine to prepare dialysis solution containing bicarbonate, calcium and magnesium. Bicarbonate with glycylglycine form a buffer with a constant pH of 7.35, which prevents reaction with calcium or magnesium and the formation of insoluble carbonate salts. This bicarbonate-based solution is stable over long periods and can be used with the same simplicity and convenience as lactate solution for peritoneal dialysis (PD) in humans.

A novel serine hydroxymethyltransferase from Arthrobacter nicotianae: characterization and improving catalytic efficiency by rational design

BACKGROUND

Serine hydroxymethyltransferase (SHMT) is the key enzyme in L-serine enzymatic production, suggesting the importance of obtaining a SHMT with high activity.

RESULTS

Here, a novel SHMT gene, glyA, was obtained through degenerate oligonucleotide-primed PCR and encoded a novel SHMT with 54.3% similarity to the known SHMT from Escherichia coli. The obtained protein AnSHMT showed the optimal activity at 40 °C and pH 7.5, and was more stable in weakly alkali conditions (pH 6.5-8.5) than Hyphomicrobium methylovorum's SHMT (pH 6.0-7.5), In order to improve the catalytic efficiency of the wild type, the site-directed mutagenesis based on sequences alignment and bioinformatics prediction, was used and the catalytic efficiency of the mutant I249L was found to be 2.78-fold higher than that of the wild-type, with the replacement of isoleucine by leucine at the 249 position.

CONCLUSIONS

This research provides useful information about the interesting site, and the application of DOP-PCR in cloning a novel glyA gene.

A serine hydroxymethyltransferase from marine bacterium Shewanella algae: Isolation, purification, characterization and l-serine production

Currently, l-serine is mainly produced by enzymatic conversion, in which serine hydroxymethyltransferase (SHMT) is the key enzyme, suggesting the importance of searching for a SHMT with high activity. Shewanella algae, a methanol-utilizing marine bacterium showing high SHMT activity, was selected based on screening bacterial strains and comparison of the activities of SHMTs. A glyA was isolated from the S. algae through thermal asymmetric interlaced PCR (TAIL-PCR) and it encoded a 417 amino acid polypeptide. The SaSHMT, encoded by the glyA, showed the optimal activity at 50°C and pH 7.0, and retained over 45% of its maximal activity after incubation at 40°C for 3h. The enzyme showed better stability under alkaline environment (pH 6.5-9.0) than Hyphomicrobium methylovorum GM2's SHMT (pH 6.0-7.5). The SaSHMT can produce 77.76mM of l-serine by enzymatic conversion, with the molecular conversion rate in catalyzing glycine to l-serine being 1.41-fold higher than that of Escherichia coli. Therefore, the SaSHMT has the potential for industrial applications due to its tolerance of alkaline environment and a relatively high enzymatic conversion rate.

Folic acid coenzymes

The above reactions involving "active formyl" and "active hydroxymethyl" groups, their interconversion, their connections with free HCOOH and HCHO, and their interdigitation with methyl groups are diagrammed in Fig. 1.

Synthesis of serine by Coxiella burnetii

Myers, W. F. (University of Kansas, Lawrence) and D. Paretsky. Synthesis of serine by Coxiella burnetii. J. Bacteriol. 82:761-763. 1961.-Enzyme preparations from suspensions of purified Coxiella burnetii are capable of synthesizing serine from formaldehyde and glycine-2-C(14) in the presence of tetrahydrofolic acid. Evidence for the reaction is obtained by isolating and identifying radioactive serine and serine derivatives. The data suggest a role for folic acid in these rickettsiae, and extend the knowledge of host-independent biosynthetic competencies of these highly parasitic microorganisms.

Syntheses with isotopically labelled carbon. Methyl iodide, formaldehyde and cyanide

Many of the uniquely labelled synthetic precursors currently employed in the design of sophisticated radiolabelled compounds have their origins in the field of hot atom chemistry. Particularly, the development during the past few years of automated, on-line synthetic procedures which combine the nuclear reaction, hot atom and classical chemistry, and rapid purification methods has allowed the incorporation of useful radionuclides into suitable compounds of chemical and biochemical interest. The application of isotopically labelled methyl iodide, formaldehyde, and cyanide anion as synthetic intermediates in research involving human physiology and nuclear medicine, as well as their contributions to other scientific methodology, is reviewed.

Effect of various concentrations of protein in chick diet upon the metabolic enzymes of glycine and serine

The effect of feeding low protein diets with and without 2% glycine or 2% L-serine to chicks upon the enzymes concerned in the matabolism of glycine and serine has been determined. D-3-phosphoglycerate dehydrogenase (EC 1.1.1.s), hosphoserine phosphatase (EC 3.1.3.3), and serine hydroxymethyltransferase (EC 2.1.2.1) activities were significantly increased in livers from chicks fed 75% protein diets as compared to liver enzyme activities from chicks fed either 24% chick starter, 2% or 25% protein diets. Phosphoserine phosphatase activity was significantly higher in kidney tissue of chicks fed 75% protein diets. Livers from chicks fed 25% protein diets had a higher activity for D-3-phosphoglycerate dehydrogenase and phosphoserine phosphatase than did those fed chick starter or 2% protein diets. D-3-phosphoglycerate dehydrogenase and phosphoserine phosphatase activities were higher in livers from chicks fed 2% protein, 2% protein + 2% glycine, and 2% protein + 2% L-serine diets when compared to those from chicks fed low protein diets with supplemental methionine or cysteine. Serine dehydratase (EC 4.2.1.13), glycerate dehydrogenase (EC 1.1.1.29) and hydroxypyruvate-P: L-glutamate transaminase activities remained constant in livers from chicks fed all experimental diets. The uric acid concentration was significantly increased in plasma from chicks fed the high protein diets which suggests that D-3-phosphoglycerate dehydrogenase, phosphoserine phosphatase and serine hydroxymethyltransferase activities were increased because of the high requirement for glycine in uric acid formation. The 75% protein diet provided three times as much glycine as the 25% protein diet which may have met the increased need for glycine for uric acid formation.

Distribution studies of glycine and serine enzymes in chicks

Day-old broiler type chicks were fed a practical starter ration for three weeks, sacrificed and the D-3-phosphoglycerate dehydrogenase (E.C.1.1.1.s), phosphoserine phosphatase (E.C.3.1.3.3.), glycerate dehydrogenase (E.C.1.1.1.29), hydroxypyruvate-P: glutamate transaminase, serine transhydroxymethylase (E.C.2.1.2.1), and serine dehydratase (E.C.4.2.1.13) enzyme activities were determined in liver, kidney, heart, spleen and brain tissue in evaluating glycine and serine metabolism. The distribution of the various glycine and serine biosynthetic enzymes in the chick tissues studied show that the major portion of glycine and serine synthesis occurs in hepatic tissue via the "phosphorylated pathway".

THE INTERCONVERSION OF GLYCINE AND SERINE IN ZEA MAYS

Glycine and formaldehyde are converted into serine in the presence of a dialyzed, lyophilized enzyme preparation from corn seedlings, with tetrahydropteroylglutamic acid and pyridoxal phosphate as coenzymes. The equilibrium constant of the reaction was calculated for the system at 37.5 °C as K = 3.1 × 103. The pH activity curve showed a maximum between 6.6 and 7.0. The effects of the concentrations of the coenzymes were studied. The glycine–serine interconverting enzyme is present throughout the seedling and occurs exclusively in the soluble fraction of the cells.

THE INTERCONVERSION OF GLYCINE AND SERINE IN ZEA MAYS

Glycine and formaldehyde are converted into serine in the presence of a dialyzed, lyophilized enzyme preparation from corn seedlings, with tetrahydropteroylglutamic acid and pyridoxal phosphate as coenzymes. The equilibrium constant of the reaction was calculated for the system at 37.5 °C as K = 3.1 × 103. The pH activity curve showed a maximum between 6.6 and 7.0. The effects of the concentrations of the coenzymes were studied. The glycine–serine interconverting enzyme is present throughout the seedling and occurs exclusively in the soluble fraction of the cells.