Sequencing of peptides and proteins with blocked N-terminal amino acids: N-acetylserine or N-acetylthreonine.

The N-Terminal Amino Acids of Human Plasma Proteins

A study has been made of the N-terminal amino acid pattern of human plasma proteins under normal and pathological conditions. The normal pattern shows the following N-terminal amino acids in order of diminishing quantities: aspartic acid, glutamic acid, valine, alanine, tyrosine, leucines, and glycine. In healthy individuals this pattern is qualitatively stable with moderate quantitative differ...

Enzymatic N-terminal addition of noncanonical amino acids to peptides and proteins.

Reactions of N-ethylmaleimide with peptides and amino acids.

N-Ethylmaleimide (NEM) has been much used for the chemical modification of proteins, and it is usually assumed that reaction occurs specifically at the thiol groups of cysteinyl residues. However, NEM has been shown to react also with the acamino group of peptides and with the imidazole group of histidine (Smyth, Nagamatsu & Fruton, 1960), and with the a-amnino group of certain amino acids (Smy...

Semi-automatic amino acid sequencing and d/l-configuration determination of peptides with detection of liberated N-terminal phenylthiocarbamoylamino acids

A semi-automatic method for the simultaneous determination of the sequence and the d/l-configuration of amino acids in peptides is reported. The automated sequencing program was set up based both on the yield in the cyclization/cleavage reaction with 40 mmol dm23 boron trifluoride (BF3) etherate at 48 °C for 5 min and on the recovery of anilinothiazolinone(ATZ-) amino acids extracted with ethyl...

N- and C-terminal amino acids of saliva parotin A.

During the course of an investigation into the biological activities and chemical properties of saliva parotin A it became necessary to study the chemical structure of this protein. Previous workers have reported that the molecular weight of saliva parotin A prepared from human saliva is 15,900 (Ito, Y. 1960). Proline, threonine, aspartic acid, and gluta mic acid are contained in saliva parotin...