The amino acid sequence of the porcine vasoactive intestinal octacosapeptide is His-Ser-Asp-Ala-Val-Phe-Thr-Asp-Asn-Tyr-Thr-Arg-Leu-Arg-Lys-Gln-Met-Ala-Val-L ys-Lys-Tyr-Leu-Asn-Ser-Ile-Leu-Asn-NH2. Its amino acid residues 1, 2, 6 and 7, counted from the N-terminus, are identical to those in the corresponding positions in both porcine glucagon and secretin. The residues in positions 3, 12, 13, 14 and 23 are identical to those in secretin, but not in glucagon, and position 10 is occupied by a tyrosyl and position 28 by an asparaginyl residue, like in glucagon but not in secretin. If in addition to identical amino acid residues also chemically similar residues, such as isoleucine in position 26 of the octacosapeptide, as compared to leucine in secretin and glucagon, are taken into consideration then the similarity between these three polypeptides is still more evident.



At a more remote level there is some structural resemblance also between these peptides and the other four peptides from the intestinal wall, cholecystokinin-pancreozymin, motilin, the gastric inhibitory peptide and substance P, the structures of which are known.



The elucidation of the structure of the octacosapeptide was facilitated by the finding that pancreatic kallikrein preferentially cleaved only one of the three bonds in its N-terminal cyanogen bromide heptadecapeptide that are susceptible to cleavage with trypsin.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1974.tb03373.x

Structure of the porcine vasoactive intestinal octacosapeptide. The amino-acid sequence. Use of kallikrein in its determination.

Structure of the porcine LH- and FSH-releasing hormone. II. Confirmation of the proposed structure by conventional sequential analyses

Isolation and structure of hypothalamic MSH release-inhibiting hormone

Constitutive Inorganic Pyrophosphatase of Escherichia coli I. PURIFICATION AND CATALYTIC PROPERTIES

Significant differences were observed in the amount and proportion of free amino acids in different organs of Arabidopsis thaliana (L.) Heynh, ecotype Columbia. The most notable were found for proline, which formed 17-26% of the total free amino acid concentration in reproductive tissues (floret and seed), but only 1-3% of the total free amino acid concentration in vegetative tissues (rosette leaf and root). Proline accumulation was associated with tissues that had relatively low water contents. Tissues which displayed high water contents, such as rosette leaves, contained low levels of proline. A significant increase in the levels of proline accumulation occurred in plants subjected to experimentally induced low water potentials as compared to unstressed plants. For instance, an 8-10-fold increase in proline was observed in the presence of 120 mmol kg -1 NaCl or KCl, and a 20-fold increase was stimulated by 60mmol kg -1 PEG. However, in addition to the accumulation of proline, massive accumulation of Na + , K + and Cl - ions occurred in tissues of plants stressed with salt. No significant differences were observed in mineral ions in plants stressed with PEG. Isotope tracer experiments with 14 C compounds established that glutamate, ornithine and arginine are precursors of the proline biosynthesis induced by PEG in response to low water potentials in Arabidopsis thaliana. We conclude that the accumulation of proline in response to PEG occurs through increased biosynthesis.

Regulation of proline accumulation in Arabidopsis thaliana (L.) Heynh during development and in response to desiccation

The rapid resolution of naturally occurring amino acids by thin-layer chromatography

An improved technique for the analysis of amino acids and related compounds on thin layers of cellulose Part I. Qualitative separation

An improved technique for the analysis of amino acids and related compounds on thin layers of cellulose. II. The quantitative determination of amino acids in protein hydrolysates.

J.G. Heathcote

Papers

The rapid resolution of naturally occurring amino acids by thin-layer chromatography

An improved technique for the analysis of amino acids and related compounds on thin layers of cellulose Part I. Qualitative separation

An improved technique for the analysis of amino acids and related compounds on thin layers of cellulose. II. The quantitative determination of amino acids in protein hydrolysates.