Reversible Chemical Modification of Protein by 2-Methoxy-5-nitrotropone

Tamaoki, Haruhiko; Murase, Yasuhiro; Minato, Sadamasa; Nakanishi, Kazuo

doi:10.1093/oxfordjournals.jbchem.a128638

Cited by 44 publications

(17 citation statements)

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“…Nitrotroponylation was performed according to the procedure of Tamaoki hydrazine at pH 9.0 for 2 h at 37 "C. The amount of nitrotroponyl residues introduced and removed was controlled by the measurements of absorbance of the purified glycoproteins at 420 nm; the value of a molar absorption coefficient for nitrotroponyl residue was taken according to Tamaoki et al [21] as 20700 M-' cm-l. After all modifications and after all procedures of release of reversibly blocking residues, glycoproteins were purified from the excess of reagents either by exhaustive dialysis or by gel filtration on Sephadex G-25, and then lyophilized.…”

Section: Reversible Blocking Of Amino Groupsmentioning

confidence: 99%

Modification of Amino Groups of Human‐Erythrocyte Glycoproteins and the New Concept on the Structural Basis of M and N Blood‐Group Specificity

Lisowska¹,

Duk²

1975

European Journal of Biochemistry

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1.Various kinds of modification of amino groups of M and N blood group glycoproteins abolished their capacity to inhibit rabbit and human anti-M and anti-N sera.2. The reversible modification of amino groups revealed that M and N blood group activity was restored after the removal of amino-group-blocking residues.3. Modification of amino groups had an entirely different effect on the reactivity of red cell glycoproteins with Vicia graminea agglutinin. The serological activity of N glycoprotein towards Vicia graminea anti-N agglutinin was unchanged, whereas the weak activity of M glycoprotein towards this anti-N agglutinin was increased to the level of that of N glycoprotein.4. These results indicate that there is a structural difference between M and N glycoproteins, which resides beyond the oligosaccharide chains. It suggests in turn that M and N blood group specificity is determined by amino acid sequence in the peptide chains of red cell glycoproteins.The M and N blood group receptors are located on the major glycoprotein of human erythrocyte membrane. It has been known that for M and N blood group activity sialic acid residues are required [l -71, and that this activity is associated with alkali-labile, sialic-acid-rich oligosaccharide chains [8 -101. Springer et al. [11,12] reported that N receptors were differentiated from M receptors by the presence of terminal b-galactosyl residues. The small amount of specific receptors among many unspecific oligosaccharide chains could justify the fact that no conclusive chemical evidence for the difference in structure of oligosaccharides of M and N glycoproteins has been reported so far. We found [13] that modification of amino groups of the glycoproteins abolished their capacity to inhibit rabbit anti-M and anti-N sera, and this finding was confirmed later by Ebert et ul. [4]. It drew attention to the possible role of the peptide chain in M and N blood group activity.The activity of red cell glycoproteins against anti-N lectin from Viciu graminea seeds (NVg activity) has entirely different structural requirements. The NV, activity is also confined to alkali-labile Abbreviation. Nyg activity, the serological activity directed toward Viciu graminea anti-N agglutinin.oligosaccharide chains [8], but is significantly enhanced after the release of sialic acid from the glycoproteins [14-161. The increase of Nvg activity on desialization of M and N antigens reached for both antigens a similar level. The Nvg activity was not affected by the modification of amino groups of N glycoprotein To shed more light on the structural differences between M and N antigenic determinants, further experiments on the modification of erythrocyte glycoprotein amino groups were undertaken, with special attention to the following problems. (a) The significance of amino groups in the reaction of glycoproteins with human anti-M and anti-N sera; (b) the reversibility of the serological effects of modification of amino groups, and (c) the effect of modification of amino groups on the NYg activity of...

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Section: Reversible Blocking Of Amino Groupsmentioning

confidence: 99%

Modification of Amino Groups of Human‐Erythrocyte Glycoproteins and the New Concept on the Structural Basis of M and N Blood‐Group Specificity

Lisowska¹,

Duk²

1975

European Journal of Biochemistry

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“…2 Reaction with iodoacetate: The 30S ribosomes were suspended in TKM buffer, adjusted to pH 8.2, and treated with a 5-fold excess of [14C ]iodoacetic acid (New England Nuclear) over potentially available SH functions; after 20 miti at 370C, the reaction was terminated with a 10-fold excess of j3-inercaptoethanol. '2 Reaction with 2-methoxy-5-nitrbtropone: 30S ribosomes were reacted with 2-methoxy-5-nitrotropone (MNT) 13 under conditions such that complete reaction was achieved without altering their sedimentation velocity. The buffer used was 20 mM veronal-10 mM KCl-5 mM MgC12, pH 8.5.…”

mentioning

confidence: 99%

Three-Dimensional Organization of the 30S Ribosomal Proteins from Escherichia coli , I. Preliminary Classification of the Proteins

Craven

Gupta

1970

Proc. Natl. Acad. Sci. U.S.A.

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Abstract. 30S ribosomal subunits from Escherichia coli were reacted with three protein reagents. After reaction, the ribosomal proteins were extracted and examined; of the 20 proteins known to compose the particle, nine did not react with any of the three reagents. We have tentatively classified these proteins as "internal," and the remaining eleven as "external." A strong correlation was found between these results and the sequence of assembly. Those proteins which enter the assembly process early are classed as internal, whereas those proteins found to participate later in the assembly sequence are classed as external.The 30S ribosomal subunit, isolated from Escherichia coli, consists of approximately 20 chemically distinct proteins1-4, present in no more than a single copy per particle5-7. While some of the proteins are primarily involved in assembly, others participate in various steps of protein synthesis'.One salient problem remaining is to understand the three-dimensional arrangement of these proteins. Unfortunately, the use of x-ray crystallography to probe the three-dimensional structure of the ribosome is not currently feasible.Chemical techniques, however, do seem to hold considerable promise toward elucidating the arrangement of the proteins. Protein chemists have developed and extensively studied reagents that can derivatize proteins. Many of these reagents can differentiate between "exposed" groups and "buried" groups in proteins. With some of these reagents, we classify the ribosomal proteins as to their relative accessibility.

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“…Similar modification studies on uricase were carried out with other reagents, such as acetic anhydride [ 11 ], trinitrobenzene sulfonate [ 12] and 2-methoxy-5-nitrotropone [13]. However, no dramatic reduction of enzymic activity was observed by the modification of amino groups in uricase with such reagents.…”

Section: Resultsmentioning

confidence: 54%

Modification of amino groups in Candida utilis uricase with naphthoquinone disulfonic acid in relation to the enzymic activity

Yoshida¹,

Nishimura²,

Takahashi³

et al. 1981

FEBS Letters

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Reversible Chemical Modification of Protein by 2-Methoxy-5-nitrotropone

Cited by 44 publications

References 0 publications

Modification of Amino Groups of Human‐Erythrocyte Glycoproteins and the New Concept on the Structural Basis of M and N Blood‐Group Specificity

Modification of Amino Groups of Human‐Erythrocyte Glycoproteins and the New Concept on the Structural Basis of M and N Blood‐Group Specificity

Three-Dimensional Organization of the 30S Ribosomal Proteins from Escherichia coli , I. Preliminary Classification of the Proteins

Modification of amino groups in Candida utilis uricase with naphthoquinone disulfonic acid in relation to the enzymic activity

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