Royal Society of Chemistry Amino Acids, Peptides and Proteins: Volume 9 (Specialist Periodical Reports - Amino Acids, Peptides and Proteins)

Excerpt. © Reprinted by permission. All rights reserved. Amino-Acids, Peptides, and Proteins Volume 9 A Review of the Literature Published During 1976 By R. C. Sheppard The Royal Society of ChemistryCopyright © 1978 The Chemistry Society All rights reserved. ISBN: 978-0-85186-084-8 Contents Chapter 1 Amino-acids By G. C. Barrett, 1, Chapter 2 Structural Investigation of Peptides and Proteins, 32, Chapter 3 Peptide Synthesis By E. Atherton and R. C. Sheppard, with Appendices compiled by A. V. Stachulski, 315, Chapter 4 Peptides with structural Features not Typical of Proteins By B. W. Bycroft, 395, Chapter 5 Chemical Structure and Biological Activity of Hormones and Related Compounds, 427, Chapter 6 Metal Complexes of Amino-acids, Peptides, and Proteins By R. W. Hay and D. R. Williams, 494, CHAPTER 1 Amino-acids BY G. C. BARRETT 1 Introduction The format used in this chapter in previous volumes continues to provide a suitable framework for a review of current literature of amino-acids. There is an additional advantage in retaining a particular format in that readers may more easily trace specific topics back through the recent literature. Biological aspects and patent literature are excluded as in previous volumes of this series, but no other restraints have been imposed so that hopefully all chemistry-based work has been considered for inclusion. Textbooks and Reviews. — Reference is made to relevant secondary and tertiary literature in the different sections of this chapter. 2 Naturally Occurring Amino-acids Occurrence of Known Amino-acids. — Reviews of the occurrence of non-protein amino-acids in plants place emphasis on imino-acids and on N-heterocyclic amino-acids, on D-amino-acids, and on the roles played by free amino-acids, which often exist in extraordinarily high concentrations in seeds (e.g. 5-hydroxy-L-tryptophan comprises ca. 14% dry weight of seeds of Griffonia simplicifolia). Hydroxylated amino-acids existing in the free form, and their sources, as represented in the recent literature, are: (2S, 3R,4R)-4-hydroxyisoleucine in steroidal sapogenin-yielding plants, γ-hydroxyarginine from pea seedlings and from lentil seeds (which also contain γ-hydroxyornithine and homoarginine), (2S,4R, 5R)-2-carboxy-4,5-dihydroxypiperidine (1) from seeds of Julbernardia paniculata, and its (2 S,4R, 5S)-isomer from Denis elliptical. The (2[S, 4S,5S)]-isomer of (1) is found in seeds of Isoberlinia, Brachystegia, Cryptosepalum, and Denis elliptical but this is the first report of the occurrence of the (2S,4R,5 R)-isomer (1). 2,4,5-Trihydroxy-L-phenylalanine (i.e. 6-hydroxy-dopa) has been isolated from cultures of Microspira tyrosinatica grown aerobically in tyrosine-containing media. γ-Carboxyglutamic acid, a recently-identified addition to the protein amino-acids (Vol. 8, p. 5) has been found in human urine at low concentrations. The occurrence of γ-methyl-L-glutamic acid and its γ-ethyl-, -methylene, and -ethylidene analogues in seeds of Julbernardia, Isoberlinia, Brachystegia, and Cryptosepalum has been reported. Reports of studies of basic amino-acids form a large part of a Proceedings volume; a report is included of the presence of basic and N-methylated basic amino-acids in frog tissue. Continuing studies of Reseda odorata (see Vol. 6, p. 3) reveal the presence of L-saccharopine and of 2S -amino-adipic acid. One of the major cell-wall constituents of aerobic coryneform organisms from human skin is L,L-2,6-diaminopimelic acid; however, the claim that this amino-acid exists in the free form in higher plants has been disproved, providing something of a puzzle since the diaminopimelate pathway has been invoked for the biosynthesis of lysine in higher plants. The first report of the existence of the D-enantiomer of α -amino-n-butyric acid in higher plants (legume seedling extracts) has appeared. Other structurally simple amino-acids located in plants include glycine betaine in wheat, and phenylalanine and tryptophan betaines