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C Milstein

Publications and source records attributed to C Milstein.

At least 235 records · Page 13Linked to original sources
PubMed1970

Human immunoglobulin subclasses. Partial amino acid sequence of the constant region of a gamma 4 chain.

The heavy chain of a human myeloma protein (Vin) belonging to the gamma4 subclass was subjected to tryptic digestion after reduction and carboxymethylation. Cyanogen bromide fragments were also prepared and all 19 tryptic peptides that account for one of them (the Fc-like fragment) were studied. Selected peptic peptides were isolated and provided evidence for the order of 15 of the tryptic peptides. In addition the sequence of two large peptic peptides derived from two sections of the molecule including all the interchain bridges is presented. Comparison with published data on other chains allows us to propose a sequence of gamma4 chains that extends from just before the presumed starting point of the invariable region (at about residue 113) to the C-terminal end of the chain (approx. residue 446), except for a section of about 50 residues. The results of the comparison suggest that the immunoglobulin subclasses have a recent independent evolutionary origin in different species. Implications for complement fixation and for the evolutionary origin of antibody diversity are also discussed.

Amino Acid Sequence↗
PubMed1968

Intrachain disulphide bridges in immunoglobulin G heavy chains. The Fc fragment.

The disulphide bridges of the Fc fragment (C-terminal half of the heavy chain) have been studied in several human immunoglobulins, containing heavy chains of different antigenic types (gamma1, gamma2, gamma3 and gamma4), and in heavy-chain-disease proteins. Two intrachain disulphide bridges were found to be present. The sequences appear to be identical in the Fc fragments of two types of chain studied (gamma1 and gamma3), and very similar to corresponding sequences of the Fc fragment in rabbit. These results suggest that the C-terminal half of the heavy chains is covalently folded (in a similar fashion to the light chains) with a C-terminal loop and an N-terminal loop. The similarity is emphasized by comparison of the sequence and location of the disulphide-bridged peptides of the C-terminal loop of heavy and light chains. The N-terminal loop, on the other hand, appears to be very different in Fc fragments and light chains. The C-terminal loop is the only one present in the F'c fragment.

Amino Acid Sequence↗
PubMed1968

A tryptic peptide containing a unique serine phosphate residue in rabbit phosphoglucomutase.

(32)P-labelled phosphoglucomutase was digested with trypsin after denaturation and two peptides were isolated that contained the bulk of the radioactivity bound to peptides. Both peptides appeared to derive from an identical section of the molecule. Peptic and subtilisin digests of the tryptic peptides were prepared. The resulting radioactive peptides were purified and their sequences studied. The presence of a single serine [(32)P]phosphate residue was clearly established. Difficulties in purification and low yields, especially of the tryptic peptide, prevented exhaustive sequence studies, but a tentative sequence is proposed as:Ala-Ile-Gly-Gly-Ile-Ile-Leu-Thr-Ala-SerP-His-Asx-Pro-Gly-Gly-Pro-(Asx(2),Gly)-Phe-Gly-Ile-Lys(where SerP represents serine phosphate and Asx represents aspartic acid or asparagine). The results do not support the presence of two serine phosphate residues in the denatured enzyme, but confirm previous results of a unique sequence around a single serine phosphate residue.

Amino Acid Sequence↗
PubMed1968

Immunoglobulin lambda-chains. The complete amino acid sequence of a Bence-Jones protein.

The total amino acid sequence of a lambda Bence-Jones protein has been established. The protein contains 211 residues, which include two methionine residues. Splitting with cyanogen bromide gave three fragments, the largest of which included the C-terminal half, which is common to other Bence-Jones proteins of the same type. The peptides obtained by tryptic, chymotryptic and peptic digestion were isolated and purified by paper-electrophoretic and chromatographic techniques. Reduction followed by carboxymethylation of the cysteine residues with radioactive iodoacetate was found to be a powerful tool in the isolation of some insoluble peptides. Unusual features of the molecule are the fact that it contains six cysteine residues and not five as observed in both kappa and lambda Bence-Jones proteins studied previously, and its size, which seems two residues smaller than the smallest Bence-Jones protein studied hitherto. The similarities and differences between this and other Bence-Jones proteins are discussed.

Amino Acid Sequence↗