scholarly journals The Amino Acid Composition of hydrolysates of Microbial Preparations From the Rumen of Sheep

1957 ◽  
Vol 10 (3) ◽  
pp. 384 ◽  
Author(s):  
RA Weller

Samples of bacteria and of protozoa were separated from the rumen fluids of sheep which had been fed four different types of ration. Amino acid analyses by ion-exchange chromatography were performed on hydrolysates of "whole protein" preparations of the microbial fractions.

1976 ◽  
Vol 29 (2) ◽  
pp. 11 ◽  
Author(s):  
Robert C Marshall ◽  
JM Gillespie

The present paper continues the study of the reduced and S-carboxymethylated high-sulphur proteins from mouse hair. Fractions have been obtained in a substantially purified form by fractional precipitation with ammonium sulphate at pH 6, followed by ion exchange chromatography on cellulose phosphate at pH 2�6. Approximately 80% by weight of the high-sulphur proteins fall into the ultra-high-sulphur category (carboxymethyicysteine content greater than 26 residues per 100 residues), and they cover a molecular weight range of 17000-28000. The components show a remarkable diversity in amino acid composition; for example the contents of arginine and glycine each vary by about 3 : 1. The remainder of the proteins contain 17-20 residues per 100 residues of carboxymethyicysteine, are smaller in size (molecular weight 11 500), and also show great diversity in overall amino acid composition.


1977 ◽  
Author(s):  
E. F. Plow ◽  
T. S. Edgington

Plasmic cleavage of fibrinogen to generate fragment X partially exposes a specific cryptic molecular site, fg-Eneo. This site in the E domain of the molecule is further exposed during subsequent cleavage. We now report on localization of this site which provides an incisive marker for the structural and conformational changes associated with plasmic cleavage of fibrinogen. Fg-Eneo was stable to reduction and alkylation and the chains of the E fragment were separated by ion exchange chromatography on DEAE-cellulose. An active component was obtained and subjected to molecular exclusion chromatography on Sephadex G-50 to insure removal of intact fg-E. A fg-Eneo positive chain was recovered and identified as Eγ with respect to amino-terminal tyrosine, amino acid composition, and immunochemical analysis. The fg-Eneo site was stable to tryptic degradation, and tryptic peptides were prepared and separated by multiple molecular exclusion chromatographic steps. Final separation of two peptides of similar size was achieved on the basis of carbohydrate content by affinity chromatography on Concanavalin A. Only the active peptide was bound by the lectin. Purity and identification of the active tryptic peptide as γ36–53 was established by amino acid composition and sequence. These results establish that this region of the γ chain of fibrinogen is not present at the hydrated surface of the native molecule but that, in association with plasmic cleavage and conformational changes, this site is progressively exposed and provides a dynamic marker of the cleavage sequence.


1978 ◽  
Vol 78 (1) ◽  
pp. 49-58 ◽  
Author(s):  
H. T. KEUTMANN ◽  
G. N. HENDY ◽  
M. BOEHNERT ◽  
J. L. H. O'RIORDAN ◽  
J. T. POTTS

During the isolation of human parathyroid hormone there is an extensive loss of immunoassayable hormone over the successive extraction steps, due in part to the presence of fragments that are soluble in 4% trichloroacetic acid. These fragments are derived from both the amino- and carboxyl-terminal regions of the hormone. The hormonal fractions precipitated with trichloroacetic acid were further purified by gel filtration and ion-exchange chromatography. At the final ion-exchange purification step, some preparations of the hormone eluted in multiple fractions. When the various components were characterized separately by immunoassay, amino acid composition, enzymic cleavage and partial sequence analysis, they were found to be closely comparable, although the most acidic fraction contained a blocked terminal amino group. Extraction of a number of batches of tissue permitted revision of the amino acid composition of human parathyroid hormone. Biosynthetic studies with labelled amino acids confirmed the absence of tyrosine and the presence of phenylalanine and threonine and localized these residues to definite regions of the molecule.


1968 ◽  
Vol 42 (1) ◽  
pp. 143-NP ◽  
Author(s):  
B. T. PICKERING

SUMMARY A protein capable of binding neurohypophysial hormones has been isolated from cod pituitary glands using gel filtration and ion-exchange chromatography. The cod protein which was acidic and rich in cystine had an amino acid composition closely related to those of the mammalian neurophysins. It had a maximum binding capacity of 2·2 μmole/14mg. for oxytocin, 2·1 μmole/14 mg. for [8-arginine]-oxytocin and 1·1 μmole/14 mg. for [8-arginine]-vasopressin. Thus the cod protein had a greater capacity for the endogenous pressor-antidiuretic peptide than for the analogous mammalian hormone.


1963 ◽  
Vol 16 (2) ◽  
pp. 384 ◽  
Author(s):  
AC Jennings ◽  
RK Morton

The amino acid composition of several protein fractions of developing wheat endosperm (cv. Gabo, grown in 1960 in Adelaide) was determined by ion-exchange chromatography. There were considerable differences in the compositions of the fractions extracted by pyrophosphate, acetic acid, and by sodium hydroxide. The composition of the fraction extracted by acetic acid remained relatively constant during development whereas there were changes in the compositions of the fractions extracted by pyrophosphate buffer, and by sodium hydroxide.


1955 ◽  
Vol 102 (4) ◽  
pp. 435-440 ◽  
Author(s):  
Leonard T. Skeggs ◽  
Walton H. Marsh ◽  
Joseph R. Kahn ◽  
Norman P. Shumway

A preparation of hypertensin I was purified by countercurrent distribution and was shown to migrate as a single component in starch blocks at pH 9.3 and 4.2. It had an isoelectric point of 7.7. Quantitative analysis by ion exchange column chromatography showed eight amino acids in approximately unimolar proportion: aspartic, proline, valine, isoleucine, leucine, tyrosine, phenylalanine, and arginine. There were in addition two moles of histidine.


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