A new structural class of biologically active peptide in non-mammals.
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Amino Acid Sequence↗
Biomedical subjects
J J Pisano
Publications and source records attributed to J J Pisano.
Activation of ganglionic tyrosine hydroxylase by peptides of the secretin-glucagon family: structure-function studies.
The hydroxylation of tyrosine to dopa is the rate-limiting reaction in catecholamine biosynthesis. It has been previously reported that secretin, vasoactive intestinal peptide and peptide histidine isoleucine amide, all members of the secretin-glucagon family of peptides, increase dopa synthesis in superior cervical ganglia in vitro. We report here that two other members of this peptide family, rat growth hormone-releasing factor and helodermin H38, a component of Gila monster venom, also increase the rate of dopa synthesis, while glucagon-like peptides I and II and a number of other peptides tested produce no effect. Since analogs of cAMP also increase dopa synthesis, it is of particular interest that all of the peptides that increase catechol synthesis also raise the levels of this cyclic nucleotide in the superior cervical ganglion. Helodermin H38 stimulated the rate of dopa synthesis and the level of cAMP with similar potencies (EC50S of approximately 10 nM) and with maximal effects of two- and two-fold, respectively. By either measure, rat growth hormone-releasing factor produced a two-fold increase at 10 microM and a three- to four-fold increase at 30 microM. Analogs of peptides of the secretin-glucagon family with a deletion or modification of the N-terminal histidine were much less effective in these assays at the concentrations tested than were their parent compounds, demonstrating an important role for this amino acid in conferring activity on these peptides. In addition to increasing dopa synthesis in intact tissue, incubation of ganglia with rat growth hormone-releasing factor, secretin, vasoactive intestinal peptide or peptide histidine isoleucine amide also increased the activity of tyrosine hydroxylase measured subsequently in ganglion homogenates. Thus, the peptidergic stimulation of dopa synthesis observed in the intact superior cervical ganglion appears to be due, at least in part, to the activation of tyrosine hydroxylase. Together with previous studies, these findings support the hypothesis that certain members of the secretin-glucagon family increase catecholamine synthesis in sympathetic neurons by a cAMP-dependent activation of tyrosine hydroxylase.
Amino Acid Sequence↗
Bradykinin and the gut cholinergic system.
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Acetylcholine↗
The renal kallikrein-kinin system: a look at the controversies.
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Aldosterone↗
Effects of vasopressin and bradykinin on anion transport by the rat cortical collecting duct. Evidence for an electroneutral sodium chloride transport pathway.
Our previous studies in cortical collecting ducts isolated from rat kidneys have shown that vasopressin increases both sodium absorption and potassium secretion, while bradykinin inhibits sodium absorption without affecting potassium transport. To determine which anions are affected by these agents, we perfused cortical collecting ducts from rats treated with deoxycorticosterone and measured net chloride flux, net bicarbonate flux (measured as total CO2), transepithelial voltage, and the rate of fluid absorption. Arginine vasopressin (10(-10) M in the peritubular bath) caused a sustained sixfold increase in net chloride absorption and a two- to threefold increase in the magnitude of the lumen negative transepithelial voltage. Before addition of vasopressin, the tubules secreted bicarbonate. Vasopressin abolished the bicarbonate secretion, resulting in net bicarbonate absorption (presumably due to proton secretion) in many tubules. Bradykinin (10(-9) M added to the peritubular bath) caused a reversible 40% inhibition of net chloride absorption, but did not affect the transepithelial voltage or the bicarbonate flux. We concluded: (a) that arginine vasopressin stimulates absorption of chloride and inhibits bicarbonate secretion (or stimulates proton secretion) in the rat cortical collecting duct; and (b) that bradykinin inhibits net chloride absorption in the rat cortical collecting duct without affecting transepithelial voltage or bicarbonate flux. Combining these results with the previous observations on cation fluxes described above, we conclude that bradykinin inhibits electroneutral NaCl absorption (or stimulates electroneutral NaCl secretion) in the rat cortical collecting duct.
Animals↗
Inhibition of [3H]nitrendipine binding by phospholipase A2.
Phospholipase A2 from several sources inhibited [3H]nitrendipine binding to membranes from brain, heart and ileal longitudinal muscle. The enzymes from bee venom and Russell's viper venom were most potent, having IC50 values of approximately 5 and 14 ng/ml, respectively, in all three membrane preparations. Inhibition of binding by bee venom phospholipase A2 was time- and dose-dependent. Mastoparan, a known facilitator of phospholipase A2 enzymatic activity, shifted the bee venom phospholipase A2 dose-response curve to the left. Pretreatment of brain membranes with bee venom phospholipase A2 (10 ng/ml) for 15 min caused a 2-fold increase in the Kd without changing the Bmax compared with untreated membranes. Extension of the preincubation period to 30 min caused no further increase in the Kd but significantly decreased the Bmax to 71% the value for untreated membranes. [3H]Nitrendipine, preincubated with bee venom phospholipase A2, was recovered and found to be fully active, indicating that the phospholipase A2 did not modify the ligand. It is concluded that phospholipase A2 acts on the membrane at or near the [3H]nitrendipine binding site and that phospholipids play a key role in the interactions of 1,4 dihydropyridine calcium channel antagonists with the dihydropyridine binding site.
Animals↗
Biochemical and histochemical characterization of ranatensin immunoreactive peptides in rat brain: lack of coexistence with bombesin/GRP.
An antibody to des-pyroglutamyl ranatensin (RT 2-11) has been prepared and has been used to histochemically and biochemically identify ranatensin-like immunoreactivity (irRT) in the rat brain. The most most prominent stained cell group was situated in the dorsal tegmental pons. Areas of immunoreactive fibers were found in the ventral hippocampus, septal area and the hypothalamus. A similar distribution was found by radioimmunoassay data. The distribution of irRT was compared to that of bombesin-like immunoreactivity (irBN). The two peptides have different though partly overlapping distributions. Gel filtration of brain extracts show that the molecular size of irRT is similar to that of synthetic RT. However, HPLC characterization of irRT indicated that the immunoreactive material is different from synthetic RT and also different from irBN and irGRP. These results indicate the presence of two separate peptide systems, one RT-like, the other BN-like, in the mammalian CNS.
Animals↗
Bombolitins, a new class of mast cell degranulating peptides from the venom of the bumblebee Megabombus pennsylvanicus.
Five structurally related heptadecapeptides rich in hydrophobic amino acids have been discovered in the venom of the bumblebee Megabombus pennsylvanicus. We have named them bombolitin I (Ile-Lys-Ile-Thr-Thr-Met-Leu-Ala-Lys-Leu-Gly-Lys-Val-Leu-Ala-His-Val-NH2 ), bombolitin II (Ser-Lys-Ile-Thr-Asp-Ile-Leu-Ala-Lys-Leu-Gly-Lys-Val-Leu-Ala-His-Val-NH2 ), bombolitin III (Ile-Lys-Ile-Met-Asp-Ile-Leu-Ala-Lys-Leu-Gly-Lys-Val-Leu-Ala-His-Val-NH2 ), bombolitin IV (Ile-Asn-Ile-Lys-Asp-Ile-Leu-Ala-Lys-Leu-Val-Lys-Val-Leu-Gly-His-Val-NH2 ), and bombolitin V (Ile-Asn-Val-Leu-Gly-Ile-Leu-Gly-Leu-Leu-Gly-Lys-Ala-Leu-Ser-His-Leu-NH2 ). Bombolitins are structurally and functionally very similar. They lyse erythrocytes and liposomes, release histamine from rat peritoneal mast cells, and stimulate phospholipase A2 from different sources. The threshold dose is 0.5-2.5 micrograms/ml depending on the peptide and the bioassay. Bombolitin V is as potent as the well-known melittin in lysing guinea pig erythrocytes (ED50 = 0.7 microgram/ml = 4 X 10(-7) M) and is 5 times more potent than mastoparan in causing mast cell degranulation, making it one of the most potent degranulating peptides discovered so far (ED50 = 2 micrograms/ml = 1.2 X 10(-6) M). The bombolitins represent a unique structural class of peptides but they have the same biological properties as melittin (from honeybees), mastoparan (wasps, hornets, and yellow jackets), and crabrolin (European hornets). This unusual circumstance (peptides with different amino acid sequences having the same biological properties) may be a manifestion of their amphiphilic nature, a property these peptides have in common.
Amino Acid Sequence↗
Purification and characterization of multiple forms of human plasma prekallikrein.
Prekallikrein was purified 1,200-fold in 20% yield from human plasma by DEAE-cellulose, arginyl-triazinyl-aminododecyl-agarose, Cm-Sephadex C-50, and Sephadex G-150 chromatography. Isoelectric focusing of the purified proenzyme gave seven peaks, four major ones at pH 8.6, 8.8, 9.1, and 9.3; and three others at pH 7.9, 8.3, and 9.5. The same IEF profile was obtained from plasma of four individuals of three races and both sexes and from three plasma pools, and was not altered by using diisopropyl fluorophosphate, benzamidine, or EDTA during fractionation. Each major IEF form contained Mr = 88,000 (prekallikrein I) and Mr = 85,000 (prekallikrein II) species, in increasing ratios of I:II from about 20:1 in prekallikrein 8.6 (prekallikrein with pI 8.6) to 1:1 in prekallikrein 9.3. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the four zymogens after activation by Hageman factor fragment and reduction gave an Mr = 53,000 H-chain and two L-chains, LI (Mr = 40,000) and LII (Mr = 37,000). Scanning the gels gave LI:LII ratios of 19:1, 5:1, 2:1, and 1:1 for prekallikreins 8.6, 8.8, 9.1, and 9.3, respectively, corresponding to the prekallikrein I:II ratios. The H-chain in turn was split into Mr = 33,000 and 20,000 chains, presumably by autolysis, because the cleavage was prevented by soybean trypsin inhibitor. Each major kallikrein had a pI 0.1-0.2 lower than its zymogen, but the same LI:LII ratio. The four kallikreins were indistinguishable kinetically with human plasma high-molecular weight kininogen and 15 synthetic substrates, and in correcting the activated partial thromboplastin time of prekallikrein-deficient (Fletcher) plasma.
Enzyme Activation↗
Amino acid sequence of bumblebee MCD peptide: a new mast cell degranulating peptide from the venom of the bumblebee Megabombus pennsylvanicus.
A new 28 amino acid peptide, we recently isolated from the venom of the bumblebee Megabombus pennsylvanicus. has been characterized. The peptide, Met-Cys-Ile-Cys-Lys-Asn-Gly-Lys-Pro-Leu-Pro-Gly-Phe-Ile-Gly-Lys-Ile-Cys- Arg-Lys-Ile-Cys-Met-Met-Gln-Gln-Thr-His(NH2), has been named bumblebee mast cell degranulating (MCD) peptide due to its ability to degranulate rat peritoneal mast cells, and its resemblance to the bee venom MCD peptide. Bumblebee MCD peptide, unlike bombolitins, the other mast cell degranulating heptadecapeptides of bumblebee venom, is not lytic and releases histamine at a dose as low as 0.05 micrograms/ml (1.6 X 10(-8) M).
Amino Acid Sequence↗
Control of sodium and potassium transport in the cortical collecting duct of the rat. Effects of bradykinin, vasopressin, and deoxycorticosterone.
Several factors interact to maintain precise control of electrolyte transport in the mammalian cortical collecting duct. We have studied the effects of deoxycorticosterone, arginine vasopressin, and bradykinin on net transepithelial sodium and potassium transport in isolated, perfused rat cortical collecting ducts. Chronic administration of deoxycorticosterone to rats increased both sodium absorption and potassium secretion above very low basal levels. Consequently, deoxycorticosterone-treated rats were used for all remaining studies. Arginine vasopressin (10(-10) M in the bath) caused a sustained fourfold increase in net sodium absorption and a sustained threefold increase in net potassium secretion. Bradykinin (10(-9) M in the bath) caused a reversible 40-50% inhibition of net sodium absorption without affecting net potassium transport or the transepithelial potential difference. In the perfusate, up to 10(-6) M bradykinin had no effect. We conclude: As in rabbits, chronic deoxycorticosterone administration to rats increases sodium absorption and potassium secretion in cortical collecting ducts perfused in vitro. Arginine vasopressin causes a reversible increase in net potassium secretion and net sodium absorption. Bradykinin in the peritubular bathing solution reversibly inhibits net sodium absorption, possibly by affecting an electroneutral sodium transport pathway.
Animals↗
Characterization of endogenous inhibitors of [3H]-imipramine binding and [3H]-serotonin uptake from rat serum.
The effects of rat serum extracts on the uptake of [3H]-serotonin and the displacement of [3H]-imipramine binding in rat forebrain synaptosomes and human platelets was studied. Deproteinated rat serum markedly inhibited synaptosomal [3H]-serotonin uptake in a dose-dependent and reversible manner. The crude extract was fractionated by C18-reverse phase HPLC. Three major peaks of inhibitory activity were found. One of the peaks was identified as serotonin and was significantly reduced after chronic reserpinization. The second major peak inhibited both [3H]-serotonin uptake and [3H]-imipramine binding in synaptosomes and platelets. This fraction had a minimal effect on the uptake of [3H]-norepinephrine, [3H]-dopamine or [3H]-GABA and was less effective in inhibiting [3H]-desipramine binding than [3H]-imipramine binding.
Animals↗
Amino acid sequences of helospectins, new members of the glucagon superfamily, found in Gila monster venom.
The amino acid sequences of two closely related peptides from Gila monster (Heloderma suspectum) venom are reported. Helospectin I is a 38-residue peptide, His-Ser-Asp-Ala-Thr-Phe-Thr-Ala-Glu-Tyr-Ser-Lys-Leu-Leu-Ala-Lys-Leu-Ala- Leu-Gln - Lys-Tyr-Leu-Glu-Ser-Ile-Leu-Gly-Ser-Ser-Thr-Ser-Pro-Arg-Pro-Pro-Ser-Ser, and helospectin II is a 37-residue peptide identical to helospectin I except that it lacks serine 38. Helospectins are pancreatic secretagogues with structures and bioactivities similar to vasoactive intestinal peptide and other members of the glucagon superfamily. The relative significance of helospectin-I and helospectin-II is presently unknown. Comparison of the 28 residues of vasoactive intestinal peptide with residues 1-28 of helospectin shows that identical amino acids occur in 15 positions. Since members of the glucagon superfamily have similar structures but different biological actions, it is possible that helospectin is more closely related to a mammalian peptide awaiting discovery.
Amino Acid Sequence↗
Isolation and characterization of two new peptides, mastoparan C and crabrolin, from the venom of the European hornet, Vespa crabro.
Two peptides rich in hydrophobic amino acids have been isolated from venom sacs of the European hornet, Vespa crabro. One peptide (P-2) is structurally and functionally related to the tetradecapeptide mastoparan and has been named mastoparan C. Leu-Asn-Leu-Lys-Ala-Leu-Leu-Ala-Val-Ala-Lys-Lys-Ile-LeuNH2. The other (P-1) is a tridecapeptide with a new sequence: Phe-Leu-Pro-Leu-Ile-Leu-Arg-Lys-Ile-Val-Thr-Ala-LeuNH2 which we have named crabrolin. The peptide releases histamine from rat peritoneal mast cells with a threshold of approximately 2.5 micrograms/ml (congruent to 8 microM). Crabrolin also facilitates the action of purified phospholipase A2 from different sources, but it is not quite as active as mastoparan. It is clearly less active than mastoparan in lysing erythrocytes, and it does not release amylase from dispersed guinea pig pancreatic acini. Given its unique sequence, the principal effect of crabrolin may be neither mast cell degranulation nor phospholipase facilitation, but a yet undiscovered action.
Amino Acid Sequence↗
Human plasma prekallikrein and high molecular weight kininogen decrease during parturition.
Prekallikrein and high molecular weight kininogen were measured in plasma taken from nine women during parturition. Prekallikrein decreased significantly (p less than 0.01) from 1.49 +/- 0.15 S-2302 U/ml (mean +/- SEM) in early labor to 1.26 +/- 0.13 S-2302 U/ml in the immediate postpartum period. Immunoreactive high molecular weight kininogen also significantly decreased from 76 +/- 5 micrograms/ml to 68 +/- 5 micrograms/ml one day postpartum (p less than 0.01). Both proteins rose to normal levels within two days. The data suggest that the kallikrein-kinin system is utilized during parturition.
Adult↗
Kallikrein-kinin and renin-angiotensin systems in rat renal lymph.
Rat renal lymph contains 254 +/- 17 ng/ml (means +/- SEM, N = 20) of immunoreactive glandular kallikrein. Like the immunoreactive glandular kallikrein in plasma, it is biologically inactive. Gel filtration of renal lymph reveals profiles for immunoreactive glandular kallikrein, protein, and inhibition of trypsin and kallikrein which resemble those seen for plasma except that high molecular weight plasma components are reduced or missing in renal lymph. In contrast, gel filtration of thoracic lymph reveals immunoreactive glandular kallikrein and protein profiles which are indistinguishable from those seen with plasma. Renin levels are 170-fold higher in renal lymph than in thoracic lymph while angiotensin-converting enzyme levels are only 16% those of thoracic lymph. In keeping with the high renin and low converting enzyme activities, renal lymph contains high levels of angiotensin I. Immunoreactive glandular kallikrein levels in renal lymph, thoracic lymph and plasma do not show the striking differences observed for renin.
Angiotensin I↗
Binding of [3H]bradykinin in isolated nephron segments of the rabbit.
Binding of intrinsically labeled [3H]bradykinin was studied in isolated nephron segments of the rabbit. Highest binding was observed in the cortical collecting tubule (5.76 +/- 0.34 X 10(-18) mol/mm) and the outer medullary collecting tubule (5.24 +/- 0.25 X 10(-18) mol/mm, means +/- SE, n = 6). Small but significant binding was also seen in the glomerulus, proximal straight tubule, cortical thick ascending limb of Henle's loop, and distal convoluted tubule. Lysyl-bradykinin, methionyl-lysyl-bradykinin, and tyrosine-8-bradykinin (but not des-arginine-9-bradykinin, vasopressin, angiotensins I and II, or prostaglandins) competed with [3H]bradykinin. The site of highest kinin binding (collecting tubule) is downstream from the highest concentration of kallikrein (granular portion of distal convoluted tubule). The binding data indicate that the major sites of kinin action in the kidney are the cortical and medullary collecting tubules. One action of kinins could be the stimulation of prostaglandin synthesis in the collecting tubules, which are known to actively synthesize prostaglandins.
Animals↗
Facilitation of phospholipase A2 activity by mastoparans, a new class of mast cell degranulating peptides from wasp venom.
The effect of mastoparan, Ile-Asn-Leu-Lys-Ala-Leu-Ala-Ala-Leu-Ala-Lys-Lys-Ile-LeuNH2, and related peptides on the release of arachidonic acid from egg yolk lecithin liposomes, rat peritoneal mast cells, and cultured human fibroblasts was studied. In unsonicated liposomes, labeled with 1-stearoyl-2[1-14C]arachidonyl-sn-glycero-3-phosphocholine, 5 X 10(-5) M mastoparan caused a 12-, 15-, and 50-fold increase in the production of arachidonic acid catalyzed by phospholipase A2 from bee venom, eastern diamondback rattlesnake and porcine pancreas, respectively. The stimulant effect of mastoparan and related peptides was dose-dependent and further enhanced by sonication of liposomes. In contrast, melittin, while stimulating the production of arachidonic acid by phospholipase from bee venom, was inactive with the rattlesnake and pancreatic enzymes. Melittin was also only weakly active with liposomes containing stearic acid in place of arachidonic acid. Like melittin, mastoparans stimulated phospholipase activity in tissue homogenates and caused a dose-dependent release of arachidonic acid from rat peritoneal mast cells and cultured human fibroblasts prelabeled with [14C]arachidonic acid. The heptapeptide fragments mastoparan 1-7 and mastoparan 8-14, and succinylated mastoparan were ineffective. The results suggest that mastoparan and related peptides in insect venoms act, at least in part, by stimulating phospholipase activity.
Amino Acid Sequence↗