Methionine Sulfoxide and Other Combined Amino Acids in the German Cockroach

Author(s):  
S. MARK HENRY ◽  
RICHARD J. BLOCK ◽  
THOMAS W. COOK
1978 ◽  
Vol 24 (9) ◽  
pp. 1087-1092
Author(s):  
G. J. Ikin ◽  
H. J. Hope ◽  
R. A. Lachance

Some aspects of the growth and amino acid metabolism of Corynebacterium sepedonicum, the organism responsible for potato ring rot, have been studied in synthetic media. It has been demonstrated that organic sulfur is required for growth. Methionine supports growth and can be replaced by methionine sulfoxide and cystathionine. Methionine is a micrometabolite for this species as indicated by the fact that optimum growth can be obtained in an asparagines–methionine (asn-met) containing medium when the molar ratio of these amino acids is 56:1. Increasing the proportion of methionine does not increase the growth. Both asparagine and glutamine are metabolized very quickly and provide for equivalent rapid growth unlike aspartic and glutamic acids. In the case of the last two amino acids, growth can be increased if dibasic ammonium phosphate is added to the medium although this compound alone will not support growth in the culture medium. The intracellular soluble asparagine level is extremely low in cells from the asn-met medium indicating a high rate of metabolism compared to aspartic acid. Cystine and cysteine were found to be inhibitory to the organism: they do not affect the rate of uptake of asn or met but do alter the organism's metabolism as reflected by changes in the free amino acid pool. The concentrations of cystine and cysteine required for measurable inhibition are much higher than those found in soluble amino acids of potato tubers.


2012 ◽  
Vol 58 (2) ◽  
pp. 402-410 ◽  
Author(s):  
Steinar Hustad ◽  
Simone Eussen ◽  
Øivind Midttun ◽  
Arve Ulvik ◽  
Puck M van de Kant ◽  
...  

Abstract BACKGROUND Biomarkers and metabolites related to B vitamin function and one-carbon metabolism have been studied as predictors of chronic diseases in studies based on samples stored in biobanks. For most biomarkers, stability data are lacking or fragmentary. METHODS Degradation and accumulation kinetics of 32 biomarkers were determined at 23 °C in serum and plasma (EDTA, heparin, and citrate) collected from 16 individuals and stored for up to 8 days. In frozen serum (−25 °C), stability was studied cross-sectionally in 650 archival samples stored for up to 29 years. Concentration vs time curves were fitted to monoexponential, biexponential, linear, and nonlinear models. RESULTS For many biomarkers, stability was highest in EDTA plasma. Storage effects were similar at room temperature and at −25 °C; notable exceptions were methionine, which could be recovered as methionine sulfoxide, and cystathionine, which decreased in frozen samples. Cobalamin, betaine, dimethylglycine, sarcosine, total homocysteine, total cysteine, tryptophan, asymetric and symmetric dimethyl argenine, creatinine, and methylmalonic acid were essentially stable under all conditions. Most B vitamins (folate and vitamins B2 and B6) were unstable; choline increased markedly, and some amino acids also increased, particularly in serum. The kynurenines showed variable stability. For many biomarkers, degradation (folate and flavin mononucleotide) or accumulation (pyridoxal, riboflavin, choline, amino acids) kinetics at room temperature were non–first order. CONCLUSIONS Data on stability and deterioration kinetics for individual biomarkers are required to optimize procedures for handling serum and plasma, and for addressing preanalytical bias in epidemiological and clinical studies.


Tetrahedron ◽  
1998 ◽  
Vol 54 (50) ◽  
pp. 15273-15286 ◽  
Author(s):  
Marta Vilaseca ◽  
Ernesto Nicolás ◽  
Fina Capdevila ◽  
Ernest Giralt

1946 ◽  
Vol 83 (1) ◽  
pp. 65-88 ◽  
Author(s):  
Gregory Shwartzman

The susceptibility of E. coli and Salmonella to penicillin is highest in a basal medium devoid of amino acids. Blood serum in certain concentrations, meat infusion broth, yeast extract, and casein hydrolysate interfere with the penicillin activity. The effect is apparently due to the antagonism of certain amino acids in the materials. Dicarboxyl-monoamino acids (i.e. aspartic, glutamic, and hydroxyglutamic acids and asparagine) cystine, arginine, histidine, and hydroxyproline are capable of suppressing the effect of penicilhn upon Gram-negative organisms. The antagonism of amino acids is not primarily related to their effect upon the rate of bacterial growth. It is suggested from the experiments detailed, that the antipenicillin activity is due to the effect of the amino acids upon bacterial metabolism. Prepassages in media of various concentrations of antagonistic amino acids alter the resistance of E. coli to penicillin. The changes are in inverse relation to the concentration of the antagonists. The antipenicillin activity of amino acids may be reversed significantly by dl-methionine. The substance, however, reverses only incompletely the antagonism of materials of mixed composition; i.e., casein hydrolysate, meat infusion broth, and serum. Upon addition of methionine, methionine sulfoxide, and threonine, there occurs a marked enhancement of penicillin susceptibility of broth cultures of Brucella, Eberthella, Salmonella, and Shigella. The enhancement is apparently due to the ability of this amino acid mixture to reverse effectively the action of the antagonists present in the cultures. Methionine is essential for the enhancement of penicillin susceptibility. Threonine and methionine sulfoxide facilitate the effect of methionine following a reciprocal quantitative relationship.


2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
George W. Wanjala ◽  
Arnold N. Onyango ◽  
David Abuga ◽  
Calvin Onyango ◽  
Moses Makayoto

Antibodies or some amino acids, namely, cysteine, methionine, histidine, and tryptophan, were previously reported to catalyse the conversion of singlet oxygen (1O2) to ozone (O3). The originally proposed mechanism for such biological ozone formation was that antibodies or amino acids catalyse the oxidation of water molecules by singlet oxygen to yield dihydrogen trioxide (HOOOH) as a precursor of ozone and hydrogen peroxide (H2O2). However, because HOOOH readily decomposes to form water and singlet oxygen rather than ozone and hydrogen peroxide, an alternative hypothesis has been proposed; ozone is formed due to the reaction of singlet oxygen with amino acids to form polyoxidic amino acid derivatives as ozone precursors. Evidence in support of the latter hypothesis is presented in this article, in that in the presence of singlet oxygen, methionine sulfoxide (RS(O)CH3), an oxidation product of methionine (RSCH3), was found to promote reactions that can best be attributed to the trioxidic anionic derivative RS+(OOO−)CH3 or ozone.


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