Conversion of substance P to C-terminal fragments in human plasma

Substance P is rapidly converted by enzyme(s) in human plasma to des-[Arg1Pro2]-substance P (fragment 3-11) and to des-[Arg1Pro2Lys3Pro4]-substance P (fragment 5-11). These metabolites were isolated by HPLC and partially sequenced. No evidence was obtained for deamidation of substance P in plasma or for the formation of the N-terminal tetrapeptide [Arg-Pro-Lys-Pro]. The data suggest that substance P is metabolized in human plasma by an enzyme with the specificity of dipeptidyl-aminopeptidase IV. Consistent with this hypothesis, the rate of degradation of substance P measured with an antibody directed against the N-terminal region is 2-3-fold greater than measured with a C-terminally directed antibody. The degrading activity of plasma was purified 522-fold and was eluted from a gel filtration column in the molecular weight zone 150 000-170 000 and from a chromatofocusing column in the pH range 4.5 to 5.5.     

Primary structures of skin antimicrobial peptides indicate a close,but not conspecific,phylogenetic relationship between the leopard frogs Lithobates onca and Lithobates yavapaiensis (Ranidae)

The phylogenetic relationship between the relict leopard frog Lithobates (Rana) onca (Cope, 1875) and the lowland leopard frog Lithobates (Rana) yavapaiensis (Platz and Frost, 1984) is unclear. Chromatographic analysis of norepinephrine-stimulated skin secretions from L. onca led to the identification of six peptides with antimicrobial activity. Determination of their primary structures indicated that four of the peptides were identical to brevinin-1Ya, brevinin-1Yb, brevinin-1Yc and ranatuerin-2Ya previously isolated from skin secretions of L. yavapaiensis. However, a peptide belonging to the temporin family (temporin-ONa: FLPTFGKILSGLF.NH₂) and an atypical member of the ranatuerin-2 family containing a C-terminal cyclic heptapeptide domain (ranatuerin-2ONa: GLMDTVKNAAKNLAGQMLDKLKCKITGSC) were isolated from the L. onca secretions but were not present in the L. yavapaiensis secretions. Ranatuerin-2ONa inhibited the growth of Escherichia coli (MIC = 50 μM) and Candida albicans (MIC = 100 μM ) and showed hemolytic activity (LC₅₀ = 90 μM) but was inactive against Staphylococcus aureus. The data indicate a close phylogenetic relationship between L. onca and L. yavapaiensis but suggest that they are not conspecific species.     

Isolation and primary structure of gastrin-releasing peptide from a teleost fish, the trout (Oncorhynchus mykiss).

Immunohistochemical studies have established that fish gastrointestinal tissues contain peptides with gastrin-releasing peptide (GRP)/bombesin-like immunoreactivity, but the molecular nature of this material is unclear. In this study, the most abundant peptide that was immunoreactive towards an antiserum raised against pig GRP was isolated in pure form from an extract of the stomach of the rainbow trout (Oncorhynchus mykiss). The primary structure of the peptide was established as: Ser-Glu-Asn-Thr-Gly-Ala-Ile-Gly-Lys-Val10- Phe-Pro-Arg-Gly-Asn-His-Trp-Ala-Val-Gly20-His-Leu-Met-NH2. Although this amino acid sequence is shorter than those of mammalian GRPs by four residues, the COOH-terminal dodecapeptide is identical to the corresponding region in pig GRP. The data indicate, therefore, that the predominant molecular form of GRP in the stomach of a teleost fish is structurally more similar to mammalian GRP than to the amphibian skin peptide, bombesin.     

Autonomic neuropathy in Fabry disease: a prospective study using the Autonomic Symptom Profile and cardiovascular autonomic function tests

Background  

Fabry patients have symptoms and signs compatible with autonomic dysfunction. These symptoms and signs are considered to be due to impairment of the peripheral nervous system, but findings indicative of autonomic neuropathy in other diseases, such as orthostatic intolerance and male sexual dysfunction, are infrequently reported in Fabry disease. The aim of our study was to investigate autonomic symptoms and cardiovascular autonomic function in a large cohort of male and female Fabry patients.     

Isolation and structure of guinea pig gastric and pancreatic somatostatin

Somatostatin-14 has been isolated from guinea pig pancreas and stomach and purified to homogeneity by gel filtration, ion-exchange chromatography and reverse phase HPLC. Amino acid composition and sequence analysis indicated that guinea pig somatostatin from both tissues has the same structure as somatostatin-14 from all other mammalian species yet studied. The study has demonstrated that somatostatin-14 from gastric tissue has the same structure as the peptide from hypothalamus and pancreas.     

The primary structure of a PYY-related peptide from chicken intestine suggests an anomalous site of cleavage of the signal peptide in preproPYY.

Although the amino acid sequence of members of the pancreatic polypeptide (PP)-family of regulatory peptides has been poorly conserved during vertebrate evolution, the overall length of the peptides (36 amino acid residues) has remained constant. Nucleotide sequence analysis of cloned cDNAs and/or genomic fragments has shown the PP-related sequence immediately follows the signal peptide in the prepropeptides. A peptide tyrosine-tyrosine (PYY)-related peptide with 37 residues has been isolated from the chicken intestine, and its primary structure was established as: Ala-Tyr-Pro-Pro-Lys-Pro-Glu-Ser-Pro-Gly10-Asp-Ala-Ala-Ser-P ro-Glu-Glu-Ile-Ala-Gln20-Tyr-Phe-Ser-Ala-Leu-Arg-His-Tyr-Il e-Asn30-Leu-Val-Thr-Arg-Gln-Arg-Tyr.CONH2. The presence of an additional alanine residue at the NH2-terminus of the peptide suggests that the site of cleavage of the signal peptide in chicken preproPYY is different from the site of cleavage in other PP-family prepropeptides.