scholarly journals Identification of betacellulin as a major peptide growth factor in milk: purification, characterization and molecular cloning of bovine betacellulin

1999 ◽  
Vol 344 (3) ◽  
pp. 713-721 ◽  
Author(s):  
Andrew J. DUNBAR ◽  
Ilka K. PRIEBE ◽  
David A. BELFORD ◽  
Chris GODDARD

Betacellulin (BTC), a member of the epidermal growth factor (EGF) family of peptide growth factors, was purified from a growth-factor-enriched whey fraction of bovine milk by a combination of ion-exchange chromatography, gel-filtration chromatography, affinity chromatography and reverse-phase HPLC. Bovine BTC (bBTC) had an apparent molecular mass of 21-22 kDa on SDS/PAGE and exists in a glycosylated form. The cDNA encoding bBTC was obtained by a combination of 5ʹ and 3ʹ rapid amplification of cDNA ends (‘RACE’). The primary translation product consists of 178 amino acid residues containing a putative signal sequence, a transmembrane domain, the mature BTC domain and a cytoplasmic domain containing a highly hydrophilic Arg-Lys-rich region similar to that of mouse BTC and human BTC. The amino acid sequence of the bBTC precursor was 88% identical with human BTC and 79% identical with mouse BTC. The bBTC gene was found to be expressed in a wide range of tissues, including the mammary gland. The identification of BTC in milk raises the possibility that it has a major role in the growth and development of the neonatal gastrointestinal tract.

1968 ◽  
Vol 106 (2) ◽  
pp. 531-541 ◽  
Author(s):  
P T Grant ◽  
K. B. M. Reid

1. Insulin has been isolated by gel filtration and ion-exchange chromatography from extracts of the discrete islet tissue of cod. The final preparation yielded a single band on electrophoresis at two pH values. The biological potency was 11·5 international units/mg. in mouse-convulsion and other assay procedures. 2. Glycine and methionine were shown to be the N-terminal amino acids of the A and B chains respectively. An estimate of the molecular weight together with amino acid analyses indicated that cod insulin, like the bovine hormone, consists of 51 amino acid residues. In contrast, the amino acid composition differs markedly from bovine insulin. 3. Oxidation of insulin with performic acid yielded the A and B peptide chains, which were separated by ion-exchange chromatography. Sequence studies on smaller peptides isolated from enzymic digests or from dilute acetic acid hydrolysates of the two chains have established the sequential order of 14 of the 21 amino acid residues of the A chain and 25 of the 30 amino acid residues of the B chain.


1996 ◽  
Vol 151 (1) ◽  
pp. 77-86 ◽  
Author(s):  
M-L Rogers ◽  
C Goddard ◽  
G O Regester ◽  
F J Ballard ◽  
D A Belford

Abstract Transforming growth factor β (TGF-β) is one of the predominant growth factors present in milk. The concentration, molecular mass forms and stability of TGF-β in bovine milk were investigated using a standard bioassay measuring the growth inhibition of a mink lung epithelial cell line. Most of the TGF-β bioactivity in milk was found to be in a latent form, which was also retained in the whey fraction. After acid activation, the total TGF-β concentration was 4·3 ± 0·8 ng and 3·7 ± 0·7 ng TGF-β per ml of milk and cheese whey respectively. Cation-exchange chromatography at pH 6·5 was used to concentrate latent whey-derived TGF-β, which could be activated by transient exposure to extremes of pH, urea or heat. Heparin did not significantly activate milk-derived TGF-β. Neutral gel filtration of the cationic whey fraction revealed a major peak of latent TGF-β with a molecular mass of 80 kDa and a smaller peak at 600 kDa. Transient acidification of the cationic whey fraction prior to neutral gel filtration, or gel filtration under acidic conditions, released low molecular mass TGF-β from both high molecular mass peaks. Whey-derived TGF-β was purified using a five-step chromatographic procedure. An N-terminal sequence was obtained for TGF-β2, which accounted for over 85% of the TGF-β bioactivity in whey. All TGF-β activity in whey could be neutralised by a monoclonal antibody directed against TGF-β1, -β2 and -β3. The results suggest that the majority of TGF-β in bovine milk is present in a small latent complex. Journal of Endocrinology (1996) 151, 77–86


1992 ◽  
Vol 38 (9) ◽  
pp. 891-897 ◽  
Author(s):  
Hiroshi Tsujibo ◽  
Yukio Yoshida ◽  
Katsushiro Miyamoto ◽  
Chiaki Imada ◽  
Yoshiro Okami ◽  
...  

Chitinase (EC 3.2.1.14) was isolated from the culture supernatant of a marine bacterium, Alteromonas sp. strain O-7. The enzyme (Chi-A) was purified by anion-exchange chromatography (DEAE-Toyopearl 650 M) and gel filtration (Sephadex G-100). The purified enzyme showed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular size and pI of Chi-A were 70 kDa and 3.9, respectively. The optimum pH and temperature of Chi-A were 8.0 and 50 °C, respectively. Chi-A was stable in the range of pH 5–10 up to 40 °C. Among the main cations, such as Na+, K+, Mg2+, and Ca2+, contained in seawater, Mg2+ stimulated Chi-A activity. N-Bromosuccinimide and 2-hydroxy-5-nitrobenzyl bromide inhibited Chi-A activity. The amino-terminal 27 amino acid residues of Chi-A were sequenced. This enzyme showed sequence homology with chitinases from terrestrial bacteria such as Serratia marcescens QMB1466 and Bacillus circulons WL-12. Key words: marine bacterium, Alteromonas sp., chitinase.


1980 ◽  
Vol 33 (2) ◽  
pp. 153 ◽  
Author(s):  
WK Fisher ◽  
DD Koureas ◽  
EOP Thompson

Myoglobin isolated from red muscle of the gummy shark M. antarcticus was purified by gel filtration and ion-exchange chromatography on carboxymethyl cellulose in 8 M urea-thiol buffer. Amino acid analysis and sequence determination showed 148 amino acid residues. The amino terminal residue is acetylated as shown by nuclear magnetic resonance and mass spectrographic analysis of an N-terminal peptide. There is a deletion of four residues at the amino terminal end as well as one residue in the CD interhelical area relative to other myoglobins. These overall differences were also found previously in myoglobin of Heterodontus portusjacksoni.


1990 ◽  
Vol 4 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Y. Kato ◽  
T. Hirai ◽  
T. Kato

ABSTRACT Porcine prolactin cDNA clones were screened using antiserum against ovine prolactin from a cDNA library of porcine anterior pituitary, and their nucleotide sequences were determined by the chain-termination method. The nucleotide sequence of the 5′ untranslated region and part of the signal peptide region were determined by direct RNA sequencing with reverse transcriptase. The composite sequence of 957 nucleotides showed a signal sequence of 30 amino acids and a further 199 amino acids corresponding to the mature prolactin molecule. The predicted sequence confirmed the amino acid sequence determined previously by direct protein analysis, except for one amide form at residue 122 (Gln instead of the reported Glu). Northern blot analysis showed that the length of the porcine prolactin mRNA was about 1·1 kb. The porcine prolactin amino acid sequence showed 81, 80, 64, 62, 80 and 31% homology with human, bovine, rat, mouse, chick and salmon forms respectively. The identical amino acid residues showed marked clustering in four domains, two of which are highly conserved throughout a wide range of species. The hydropathy and secondary structure of porcine prolactin were analysed and compared with those of porcine GH, which shares the same ancestral gene. The two highly conserved regions of both hormones showed similar hydrophilicity, and the predicted secondary structures indicated that these regions in each hormone form different structures with differences in extension of the hydrophilic residues outside the molecule.


1979 ◽  
Vol 32 (3) ◽  
pp. 277 ◽  
Author(s):  
WK Fisher ◽  
EOP Thompson

Myoglobin isolated from red muscle of the shark H. portusjacksoni was purified by ion-exchange chromatography on sulfopropyl-Sephadex and gel-filtration. Amino acid analysis and sequence determination showed 148 amino acid residues. The amino terminal residue is acetylated as shown by mass spectrographic analysis of N-terminal peptides. There is a deletion of four residues at the amino terminal end as well as one residue in the CD interhelical area relative to other myoglobins.


1979 ◽  
Author(s):  
Takashi Morita ◽  
Craig Jackson

Bovine Factor X is eluted in two forms (X1and X2) from anion exchange chromatographic columns. These two forms have indistinguishable amino acid compositions, molecular weights and specific activities. The amino acid sequences containing the γ-carboxyglutamic acid residues have been shown to be identical in X1 and X2(H. Morris, personal communication). An activation peptide is released from the N-terminal region of the heavy chain of Factor X by an activator from Russell’s viper venom. This peptide can be isolated after activation by gel filtration on Sephadex G-100 under nondenaturing conditions. The activation peptides from a mixture of Factors X1 and X2 were separated into two forms by anion-exchange chromatography. The activation peptide (AP1) which eluted first was shown to be derived from Factor X1. while the activation peptiae (AP2) which eluted second was shown to be derived from X2 on the basis of chromatographic separations carried out on Factors X1 and X2 separately. Factor Xa was eluted as a symmetrical single peak. On the basis of these and other data characterizing these products, we conclude that the difference between X1 and X2 are properties of the structures of the activation peptides. (Supported by a grant HL 12820 from the National Heart, Lung and Blood Institute. C.M.J. is an Established Investigator of the American Heart Association).


1980 ◽  
Vol 187 (3) ◽  
pp. 647-653 ◽  
Author(s):  
K Arakawa ◽  
M Yuki ◽  
M Ikeda

Tryptensin, a vasopressor substance generated from human plasma protein fraction IV-4 by trypsin, has been isolated and the amino acid composition analysed. The procedures used for the isolation were: (a) adsorption of the formed tryptensin on Dowex 50W (X2; NH4+ form); (b) gel filtration through Sephadex G-25; (c) cation-exchange chromatography on CM-cellulose; (d) anion-exchange chromatography on DEAE-cellulose; (e) re-chromatography on CM-cellulose; (f) gel filtration on Bio-Gel P-2; (g) partition chromatography on high-pressure liquid chromatography. The homogeneity of the isolated tryptensin was confirmed by thin-layer chromatography and thin-layer electrophoresis. The amino acid analysis of the hydrolysate suggested the following proportional composition: Asp, 1; Val, 1; Ile, 1; Tyr, 1; Phe, 1; His, 1; Arg, 1; Pro, 1. This composition is identical with that of human angiotensin.


1971 ◽  
Vol 24 (3) ◽  
pp. 765 ◽  
Author(s):  
Jean E Kratzing

The amino acid sequence of the a-chain of haemoglobin from M. giganteus has been determined. The soluble peptides formed by tryptic digestion were isolated by gel filtration, ion-exchange chromatography, paper ionophoresis, and chromatography. The amino acid sequences were determined by the "dansyl"Edman procedure. Incomplete hydrolysis of one bond resulted in a large insolublecore peptide containing 40 amino acid residues. The sequence of this peptide was deduced from the sequences of smaller peptides resulting from further digestion with thermolysin and papain. Maleylation of the a-globin before tryptic digestion gave three large fragments which assisted in assigning tryptic peptides to specific areas of the molecule. A special procedure involving maleylation of a chymotryptic digest of globin was used to isolate peptides containing arginine which provided overlap sequences of tryptic peptides


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