POLYMERS OF AMINOACETALDEHYDE

1945 ◽  
Vol 23b (4) ◽  
pp. 158-163
Author(s):  
H. H. Richmond ◽  
George F. Wright
Keyword(s):  
Molecular Weight ◽  
Ammonium Chloride ◽  
Ammonium Carbonate ◽  
Hydroxyl Groups ◽  
Molecular Weight Determination ◽  
Amino Groups ◽  
Primary Amino

The compound designated by Emil Fischer as 2,5-dihydroxypiperazine has been shown to be tris-aminomethyltrioxane by molecular weight determination of its derivatives. These benzoyl and benzenesulphonyl chloride derivatives further demonstrate the absence of hydroxyl groups and the presence of primary amino groups in the original compound. It has been found that use of ammonium carbonate, but not ammonium chloride, enhances the yield of aminoacetal obtained by ammonolysis of chloroacetal.

scholarly journals The Blocked Amino-Terminal Peptide of Feather Keratin

1971 ◽  
Vol 24 (1) ◽  
pp. 179 ◽  
Author(s):  
IJ O'donnell
Keyword(s):  
Molecular Weight ◽  
Acetic Acid ◽  
Amino Groups ◽  
Amino Terminal ◽  
Acetyl Content ◽  
Electrophoretic Patterns ◽  
Isolation And Characterization ◽  
Primary Amino

Proteins extracted from reduced and carboxymethylated feather keratins (SCM-keratins) have been studied by Harrap and Woods (1964a, 1964b, 1967). They have demonstrated the presence of electrophoretic heterogeneity amongst the proteins and have obtained a molecular weight of approximately 11,000 in agreement with earlier work of Woodin (1954). There was no indication of marked heterogeneity with respect to size. Using acid hydrolysis and determination of acetic acid produced they found an acetyl content of 1 �30 molesj104 g in the rachis off owl feathers. These were thought to be attached to primary amino groups since there were no O-acetyl groups. In the present paper the isolation and characterization of the predominant, and probably sole, amino-terminal tripeptide from goose feather calamus is described. Goose feather calamus was chosen because its extracted proteins had one of the simplest electrophoretic patterns of proteins from the feathers of a number of species (Harrap and Woods 1967).

Measurement of proteolysis in cheese: relationship between phosphotungstic acid-soluble N fraction by Kjeldahl and 2,4,6- trinitrobenzenesulphonic acid-reactive groups in water-soluble N

1994 ◽  
Vol 61 (3) ◽  
pp. 437-440 ◽  
Author(s):  
Yvette Bouton ◽  
Remy Grappin
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Phosphotungstic Acid ◽  
Water Soluble ◽  
Hydroxyl Groups ◽  
Amino Groups ◽  
Reactive Groups ◽  
Primary Amino

Free amino groups produced during cheese ripening are used to indicate the extent of cheese proteolysis. Several studies have shown a high correlation between the level of free amino acids and the flavour of Gouda (Aston et al. 1983) or Comté (Grappin & Berdagué, 1989). Measurement of the level of free amino acids seems useful for the investigation of flavour chemistry in cheese (Lemieux et al. 1990). The determination of N fractions is often used to estimate the degree of proteolysis in cheese, but since this procedure is laborious and time consuming several attempts have been made to replace it by more rapid methods (Ardö & Meisel, 1991). Since its introduction by Satake et al. (1960), the 2,4,6-trinitrobenzenesulphonic acid (TNBS) method has been widely used for the determination of free amino groups. Because TNBS does not react with the imino groups of histidine and proline or the hydroxyl groups of tyrosine, serine or threonine, it has been accepted as a selective reagent for primary amino groups (Burger, 1974). Measurement of N by Kjeldahl in the phosphotungstic acid (PTA)–sulphuric acid extract (Gripon et al. 1975) estimates the N of free amino acids and low molecular mass peptides. The purpose of this study was to compare the TNBS and PTA-soluble N methods in order to find out whether the TNBS procedure can replace that of PTA-soluble N in the determination of a cheese proteolysis index.

Molecular Weight Determination of Component Polypeptides of Glutenin after Fractionation by Gel Filtration

1975 ◽  
Vol 39 (8) ◽  
pp. 1527-1531
Author(s):  
Zen-ichiro Hamauzu ◽  
Yukio Kamazuka ◽  
Hirokazu Kanazawa ◽  
Daizo Yonezawa
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Molecular Weight Determination
Sign in / Sign up

Export Citation Format

Share Document