Caseino-glycopeptides: Characterization of a methionine residue and of the N-terminal sequence

Delfour, Antoine; Jollès, Jacqueline; Alais, C.; Jollès, Pierre

doi:10.1016/0006-291x(65)90145-2

Cited by 137 publications

(41 citation statements)

References 9 publications

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“…Met*, methionine prbsente sous la forme homos6rine-homos6rine lactone; HSer, homosbrine; SerP, phosphosbrine; peptides CN, peptides obtenus par action du bromure de cyanoghe. Au cours de la phase primaire de la coagulation du lait, la prhsure hydrolyse sphcifiquement une liaison phenylalanine-methionine trks labile de la chaine peptidique de la cas6ine x [5,42], qui se scinde alors en 2 fragments: un fragment NH,-terminal appelh paracashine x, et un fragment COOH-terminal appele caseinomacropeptide dont l'h6titrog6neith reflBte celle de la caseine x, car les glucides et les substitutions d'acides aminhs diffitrmciant les variants gknetiques A et B sont prBcisement localisits dans ce fragment. Les 6lBments de structure de la caseine x connus au debut de cette etude etaient encore trits fragmentaires [4,6,7,9,43].…”

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Structure primaire du caseinomacropeptide de la caseine kappaB1 bovine

et al. 1972

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This paper deals with the amino‐acid sequence of χB1‐caseinomacropeptidc, the soluble COOH‐terminal fragment split from xB,‐casein by rennin. χB1‐casein, the major component of χB1‐casein, is devoid of carbohydrate and was used as starting material. This component, which contains 2 methionyl residues [1‐3], was cleaved with cyanogen bromide. The 3 expected peptides, designated as CN peptides, were separated first on Sephadex G‐50 and further purified on Dowex 50‐X2. Peptide χB1CN2, which is 63 residues long, is the COOH‐terminal part of χB1‐casein chain according to the following observations : it is devoid of homoserine‐homoserine lactone; the 11 amino acids released by carboxypeptidase A are those of the COOH‐terminal end of χ‐casein [4]. Peptide χB1CN2 represents the χB1‐caseinomacropeptide devoid of its NH2‐terminal methionyl residue [5‐7]. Its complete amino‐acid sequence was determined by classical methods, using thermolysin to produce smaller fragments, then exopeptidases and chemical procedures, such as subtractive Edman degradation and hydrazinolysis, for establishing the structure of these fragments. Overlapping of the 11 “thermolysin” peptides was obtained by studying peptic fragments from χB1CN2. The sequence of the first 18 amino acids at the NH2‐terminal end is identical with that reported earlier by Jollès' group [8,9] The COOH‐terminal sequence is identical to those respectively reported by Jollès and Alais [1,10] and Malpress et al. [7], but it is only in partial agreement with those suggested by De Koning et al. [6] and Pujolle et al. [4]. From sequence data of peptide χB1CN2, is has been concluded that χB1‐caseinomacropeptide is a single polypeptide chain containing 64 amino acid residues: Asp1, Asn3, Thr11, Ser5, SerP1, Glu8, Gln2, Pro8, Gly1, Aha6, Val6, Met1, Ile7, Leu1, Lys3, and its molecular weight has been calculated to be 6755. There is a higher number of acidic than basic residues and the negative net charge of the molecule has been estimated to be 7.5 at pH 6.8. Since Bigelow's parameter for the average hydrophobicity [11] is 1083, χB1‐caseinomacropeptide can be considered to be rather hydrophobic. The sequence obtained emphasizes the uneven charge distribution along the polypeptide chain: the 3 lysyl residues are located at the NH2‐terminal end, and the 32‐53 region contains 7 of the total 10 acidic residues. Another remarkable feature of the chain is the great number of hydroxy‐amino acid residues : one in four of the total 64 residues is serine or threonine, and this relative proportion rises to one in three in the 12‐64 region. According to Hill and Wake [12], this distribution might be intimately associated with the micelle‐stabilizing properties of χ‐casein. As expected from the high amount of some amino acids, and thc lack of cysteine, arginine, histidine, phenylalanine, tyrosine and tryptophane, many regions in the caseinomacropeptide have identical or very similar structures. Therefore, some difficulties were encountered when ovcrlapping the “thermolysin” peptides. The high a...

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Structure primaire du caseinomacropeptide de la caseine kappaB1 bovine

et al. 1972

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“…When milk is hydrolyzed with chymosin during cheesemaking, -CN is hydrolyzed into two portions: one remains in the cheese (para--CN) and the other (CMP) is lost in whey; the latter is relatively small, with 63 residues and a MW of ca. 8 kDa [52]. Further to its polymorphisms, CMP may exist in various forms depending on the extent of post-transcriptional changes: it glycosylates through an O-glycoside bridge, and phosphorylates via a Ser residue.…”

Section: Caseinomacropeptide (Cmp)mentioning

confidence: 99%

Whey Proteins as Source of Bioactive Peptides Against Hypertension

Tavares¹,

Malcata²

2013

Bioactive Food Peptides in Health and Disease

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“…It is known that chymosin (EC 3.4.23.4) or pepsin (EC 3.4.23.3) cleave the single Phe"'-Metlo bond in Xcasein, this event triggering coagulation [5].…”

Section: Growth Of Myxobacteriamentioning

confidence: 99%

A chymosin‐like extracellular acidic endoprotease from Myxococcus xanthus DK101

Carias¹,

Raingeaud

Mazaud³

et al. 1990

FEBS Letters

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SDS-PAGE and N-terminal sequence analysis of hydrolysis products from 3 substrates containing a unique sensitive bond usually recognized by chymosin (rc-casein, a synthetic hexapeptide and a recombinant tripartite protein) revealed that a 45 kDa endoprotease of Myxococcus xanrhus DKlOl cleaved the same characteristic Phe-Met bond with high specificity. Such an enzyme, easy to obtain from culture supematant and to use in acidic conditions, could be a new tool for protein engineering.

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Caseino-glycopeptides: Characterization of a methionine residue and of the N-terminal sequence

Cited by 137 publications

References 9 publications

Structure primaire du caseinomacropeptide de la caseine kappaB1 bovine

Structure primaire du caseinomacropeptide de la caseine kappaB1 bovine

Whey Proteins as Source of Bioactive Peptides Against Hypertension

A chymosin‐like extracellular acidic endoprotease from Myxococcus xanthus DK101

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