Per Fernlund

Crustacean Color-Change Hormone: Amino Acid Sequence and Chemical Synthesis

The blanching hormone of the prawn, Pandalus borealis, is pGlu-Leu-Asn-Phe-Ser-Pro-Gly-Trp-NH2. Its structure was settled by a combination of mass spectrometry and Edman-dansyl analysis of a thermolysin fragment. Confirmation of the structure was obtained by chemical synthesis from amino acids. This neurosecreted hormone is active in picogram amounts when tested in shrimps.

Structure of a light-adapting hormone from the shrimp, Pandalus borealis.

The structure of a light-adapting hormone of the shrimp, Pandalus borealis, has been determined. The hormone, which had been isolated from Pandalus eyestalks and which adapts the shrimp to brighter light conditions by causing the pigment in the distal retinal pigment cells of the eye to move into a more proximal position, is the peptide: Asn-Ser-Gly-Met-Ile-Asn-Ser-Ile-Leu-Gly-Ile-Pro-Arg-Val-Met-Thr-Glu-Ala-NH2. The structure was obtained by sequence analysis by the dansyl-Edman method of the intact hormone and of isolated tryptic and thermolytic peptides.

β-Cell Function in Relation to Islet Cell Antibodies During the First 3 Yr After Clinical Diagnosis of Diabetes in Type II Diabetic Patients

OBJECTIVE— To determine the effects of islet cell antibodies on β-cell function during the first 3 yr after diagnosis in type II diabetic patients. RESEARCH DESIGN AND METHODS— β-cell function in type II diabetic patients with (n = 11, 50 ± 5 yr of age) and without (n = 10, 52 ± 4 yr of age) ICA was followed prospectively and compared with β-cell function in type I adult diabetic patients (n = 17, 37 ± 5 yr of age) and in healthy control subjects (n = 34, age 45 ± 3 yr). β-cell function was evaluated as fasting C-peptide, 1 + 3 min C-peptide after intravenous glucose, and ∆ C-peptide after glucagon. RESULTS— Fasting C-peptide was equal in type II diabetic patients with ICA (0.30 ± 0.03 nM) and type I diabetic patients (0.24 ± 0.03 nM) at diagnosis, and decreased (P < 0.05) during 3 yr in these groups but not in type II diabetic patients without ICA. At diagnosis, type II diabetic patients with ICA showed a 1 + 3 min C-peptide (0.92 ± 0.17 nM) lower (P < 0.001) than control subjects but higher (P < 0.05) than type I diabetic patients (0.53 ± 0.11 nM). After 1 yr, 1 + 3 min C-peptide in type II diabetic patients with ICA had decreased (P < 0.05) to 0.18 ± 0.11 nM and was equal to type I diabetic patients (0.38 ± 0.10 nM). ∆ C-peptide after glucagon was equally impaired in type II diabetic patients with ICA (0.38 ± 0.06 nM) and type I diabetic patients (0.35 ± 0.11 nM) at diagnosis. After 3 yr, type II diabetic patients with ICA had fasting C-peptide of 0.09 ± 0.04 nM, 1 + 3 min C-peptide of 0.18 ± 0.10 nM, and ∆ C-peptide after glucagon of 0.20 ± 0.09 nM, values equal to type I diabetic patients but lower (P < 0.01) than in type II diabetic patients without ICA, whose values remained unchanged; fasting C-peptide of 0.97 ± 0.17 nM, 1 + 3 min C-peptide of 2.31 ± 0.50 nM, and ∆ C-peptide after glucagon of 1.76 ± 0.28 nM. CONCLUSIONS— In patients considered type II diabetic with ICA, β-cell function progressively decreased after diagnosis, and after 3 yr was similar to type I diabetic patients, whereas β-cell function in type II diabetic patients without ICA was unchanged.

Purification and characterization of two proteins with Co-lipase activity from porcine pancreas

Abstract Two co-lipases, named co-lipases I and II, have been isolated from extracts of porcine pancreatic gland. The two proteins can be separated by ion-exchange chromatography and disc electrophoresis. They probably have identical amino acid compositions and have the same sequence of nine N-terminal amino acids. They contain the same number of acidic and basic amino acids and therefore most probably only differ in the extent of amidation of their glutamic and aspartic acid residues. Two co-lipases also exist in porcine pancreatic juice. A co-lipase previously purified from the porcine pancreatic gland and reported to have an N-terminal isoleucine had lost six N-terminal amino acids most probably during the purification procedure. The biological activity of this co-lipase and those described here is, however, the same.

Structure of the red-pigment-concentrating hormone of the shrimp, Pandalus borealis

The structure of a crustacean hormone secreted by nerve cells, the red-pigment-concentrating hormone (blanching hormone) of the shrimp, Pandalus borealis, has been determined. About 100 μg of hormone, purified from shrimp eyestalks, was used. The structure, which is < Glu-Leu-Asn-Phe-Ser-Pro-Gly-Trp-NH2, was revealed by thermolysin digestion and separation by Sephadex G-25 chromatography of the resulting two fragments. One fragment was the NH2-terminal peptide, < Glu-Leu-Asn, whose structure was determined by carboxypeptidase digestion and identification of the products in the automatic amino acid analyser and by thin-layer chromatography; that of the other, Phe-Ser-Pro-Gly-Trp-NH2, which was a COOH-terminal fragment, was determined by the dansyl-Edman technique. The COOH-terminal residue was identified by comparison of its 1-dimethylaminonaphthalene-5-sulfonyl (Dns) derivative with synthetic Dns-Trp-NH2 by polyamide thin-layer chromatography.

Chromactivating hormones of Pandalus borealis; Isolation and purification of a light-adapting hormone

Abstract 1. 1. Light-adapting hormone activity (distal-retinal-pigment hormone) from eyestalks of the prawn Pandalus borealis was purified by partition between an organic and an aqueous phase in two different systems and subsequent chromatography on Sephadex G-25. It was then separated into 4 chemically different components by chromatography on CM-Sephadex. 2. 2. The main component was prepared in pure form by chromatography on Sephadex G-25 (superfine). It was homogeneous according to paper electrophoresis and thin-layer chromatography. About 1.8 mg were obtained from 226 g of lyophilized eyestalks, comprising about 19% of the original biological activity. 3. 3. The hormone was easily oxidized by atmosphoric O 2 , and thiodiglycol was employed as an antioxidant during the purification. 4. 4. The hormone is an octadeca-peptide (molecular weight about 2000) and it contains 12 different amino acid residues, among which are one arginine and two methionine residues but not aromatic amino acid residues. Its N-terminal acid residue has no free amino group.

A cDNA coding for human sex hormone binding globulin Homology to vitamin K-dependent protein S

Affinity purified antibodies to human sex hormone binding globulin (SHBG) were used in screening a human liver cDNA library, constructed in the expression vector λgt 11. One clone, identified as producing recombinant SHBG, carried a cDNA insert of 1.1 kb. The nucleotide sequence of the insert had an open reading frame coding for 356 amino acid residues. The coding sequence was followed by a short 3′‐region of 19 non‐translated nucleotides and a poly(A) tail. Confirmation that the cDNA clone represented human SHBG was obtained by the finding of a complete agreement in amino acid sequence with several peptide fragments generated from purified SHBG by proteolytic cleavage. The primary structure of SHBG shows a considerable homology to that of protein S, a vitamin K‐dependent protein with functions in the coagulation system.

Chromactivating hormones of Pandalus borealis isolation and purification of the ‘red-pigment-concentrating hormone’

Abstract 1. 1. ‘Red-pigment-concentrating hormone’ and distal retinal pigment hormone from aqueous extract of lyophilized eyestalks of Pandalus borealis have been separated on Sephadex G-25. 2. 2. Low activity yields (30%) of the distal retinal pigment hormone were increased by combining the active material with separated inactive material. 3. 3. Final purification of the ‘red-pigment-concentrating hormone’ has been achieved by repeated chromatography on Sephadex LH-20 using different mixtures of water and butanol as solvent. 4. 4. The purified ‘red-pigment-concentrating hormone’ has a specific activity of 1.7·10 6 times that of dry eyestalks. The total recovery of hormone activity was about 35%. 5. 5. A reference standard for the ‘red-pigment-concentrating hormone’ is described and a unit of ‘red-pigment-concentrating hormone’ is defined. 6. 6. The hormone is a peptide containing the eight amino acids, aspartic acid, glutamic acid, glycine, leucine, phenylalanine, proline, serine and tryptophan. 7. 7. No N-terminal amino group has been found. 8. 8. Large and small erythrophores in Palaemon adspersus are both affected by this hormone.

Gender, Autoantibodies, and Obesity in Newly Diagnosed Diabetic Patients Aged 40–75 Years

OBJECTIVE To evaluate the frequency of autoimmune markers (islet cell antibodies [ICA] and glutamic acid decarboxylase antibodies [GADA]) and clinical features in newly diagnosed people with diabetes aged 40–75 years. RESEARCH DESIGN AND METHODS Two hundred fifty-nine consecutive patients (aged 40–75 years) with newly suspected diabetes diagnosed during a 2-year period were studied. The diagnosis of newly discovered diabetes was confirmed in 203 patients. Gender, BMI, HbAic, fasting C-peptide, ICA, and GADA were evaluated. The frequency of obesity was estimated using two different sets of criteria: 1) National Diabetes Data Group (NDDG) criteria, and 2) criteria based on a Swedish reference population. RESULTS The annual incidence of diabetes was 106 per 100,000 people. The incidence of diabetes in those patients who were 40–54 years old was significantly higher in men than in women (odds ratio: 2.16; P = 0.001). ICA were detected in 16 of 203 patients (8%), whereas 17 of 203 patients (8%) were GADA+; 10 of 203 (5%) patients were positive for both ICA and GADA. Among the 203 diabetic patients, 19 (9.4%) were classified as having IDDM, giving an IDDM incidence of 10 per 100,000 people aged 40–75 years. The frequency of obesity in NIDDM was high but varied with its definition; the frequency of obesity was highest (P < 0.001) when NDDG criteria, and not Swedish reference values, were used (57 of 75 [76%] vs. 40 of 75 [53%] for women and 66 of 109 [61%] vs. 45 of 109 [41%] for men). CONCLUSIONS A striking male preponderance was found among incident cases of diabetes in people aged 40–54 years. Autoimmune markers were detected in 10% of incident cases of diabetes in people aged 40–75 years. Using a conservative estimation, as many as 10 of 100,000 middle-aged and elderly subjects developed IDDM. The frequency of obesity in NIDDM was high but this was also the case in the reference population.

Glutamate decarboxylase antibody levels predict rate of β-cell decline in adult-onset diabetes

Glutamate decarboxylase autoantibodies (GAD65Ab) and beta-cell function were evaluated at and 3 years after diabetes onset in consecutive subjects over 15 years of age. At onset, 21/32 (66%) insulin-treated patients (mean age 43, range 16-79 years) had GAD65Ab; all GAD65Ab persisted 3 years later. At onset, 20/82 (24%) non-insulin-treated patients (mean age 56, range 20-79 years) had GAD65Ab. Of those with persistent GAD65Ab, 8 non-insulin-treated and 11 insulin-treated patients consented to follow-up glucose and glucagon stimulation tests. For non-insulin-treated patients, quantitative GAD65Ab index at onset correlated inversely with 1 + 3 min C-peptide response to glucose (r = -0.68, P < 0.05) and to glucagon (r = -0.79, P < 0.05) 3 years later. Those with high (> 0.50) initial GAD65Ab index had lower C-peptide (fasting, 1 + 3 min after glucose and after glucagon) 3 years later, versus those with low (< 0.50) initial GAD65Ab index (P < 0.05). In conclusion, not only did GAD65Ab presence predict future insulin dependence, but higher GAD65Ab levels may mark more rapid decline in beta-cell function in apparent non-insulin-dependent diabetes.