Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Isothiocyanates”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
PubMed1998

Analysis of fluorescein isothiocyanate derivatized amphetamine and analogs in human urine by capillary electrophoresis in chip-based and fused-silica capillary instrumentation.

Amines can easily be derivatized with fluorescein isothiocyanate isomer I (FITC) and analyzed by capillary electrophoresis (CE) using alkaline buffers with or without dodecyl sulfate micelles. This paper reports the CE analysis of FITC-derivatized amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine and beta-phenylethylamine in human urine using chip-based and fused-silica capillary instrumentation with laser-induced fluorescence detection. Data obtained via direct labeling of fortified urine are compared to those generated after FITC labeling of urinary extracts that were prepared by solid-phase extraction using a copolymer phase. For a urine volume of 5 mL with a "spiked amine": FITC ratio of 1:250, the latter approach was found to provide a sensitivity that is relevant for toxicological drug screening and confirmation (about 200 ng/mL urine). With direct labeling of 10 microL urine that was alkalinized and diluted for derivatization, the limit of identification was determined to be about 10 microg/mL, a value that is too high for practical purposes. Compared to fused-silica capillaries, electrophoresis in microstructures is shown to provide faster separations and higher efficiencies without loss of accuracy and precision.

Amphetamines↗
PubMed1988

Short-term toxicity study of allyl isothiocyanate in rats.

Allyl isothiocyanate (AITC) was given in doses of 0, 10, 20, or 40 mg/kg (5 days/week) by oral intubation to male rats for up to 6 weeks. The highest dosage level caused a decrease in body weight, thymus weight, blood glucose and serum globulin levels. Haematological examination revealed an increased percentage of neutrophils and a decreased percentage of lymphocytes after treatment for 2 weeks. Increased liver and adrenal weights were found in all test groups. Renal dysfunction was indicated by increased urinary aspartate amino-transferase activity, reduced urine volume and changes in the specific gravity of the urine. Histopathological changes were observed in the kidneys of animals at dosages of 20 and 40 mg/kg and in the livers of animals at the highest dosage level.

Animals↗
PubMed1992

Subacute oral toxicity study of benzyl isothiocyanate in rats.

The subacute toxicity of benzyl isothiocyanate (BITC) was investigated in male rats given oral doses of 0, 50, 100 and 200 mg/kg body weight/day for 4 weeks. Body weight gain and food consumption were decreased with increasing doses of BITC. Haematological changes of toxicological relevance were observed in the highest dose group. BITC administration resulted in increased serum cholesterol level in all treatment groups and decreased serum triglycerides level at 200 mg/kg. Renal dysfunction was indicated by reduced urine volume, proteinuria and enhanced urinary lactate dehydrogenase activity. BITC exposure also affected the weights of various organs and caused histological changes in the ductus choledochus, liver, ileum and mesenteric lymph nodes.

Animals↗
PubMed1995

Some aspects of reactions of benzyl isothiocyanate with bovine sarcoplasmic proteins.

Benzyl-ITC (benzyl isothiocyanate) reacts preferentially with amino groups and sulfhydryl side chains of bovine sarcoplasmic proteins to form thiourea and dithiocarbamate derivatives, generally resulting in a decrease in solubility of the derivatives along a wide pH range. Under these conditions, it was also possible to show that secondary amine side chains, as found in tryptophan, also react with benzyl-ITC. A quenching of tryptophan fluorescence intensity after interaction with benzyl-ITC was also observed. Polyacrylamide gel electrophoresis (PAGE) experiments in the presence of urea indicated changes in electrophoretical mobility and in composition of subfractions. Changes in surface hydrophobicity and composition as determined by the ANS (8-anilinonaphthalene-1-sulfonate) method and RP-HPLC were also observed. Polymerisation of protein molecules after reaction with benzyl-ITC was documented using the SDS-PAGE technique. These investigations showed that a group of subfractions belonging mainly to glycolytic enzymes and associated proteins with molecular weight between 38-70 kDa was highly reactive.

Animals↗
PubMed2007

Observation of an unusually facile fragmentation pathway of gas-phase peptide ions: a study on the gas-phase fragmentation mechanism and energetics of tryptic peptides modified with 4-sulfophenyl isothiocyanate (SPITC) and 4-chlorosulfophenyl isocyanate (SPC) and their 18-crown-6 complexes.

Various peptide modifications have been explored recently to facilitate the acquisition of sequence information. N-terminal sulfonation is an interesting modification because it allows unambiguous de novo sequencing of peptides, especially in conjunction with MALDI-PSD-TOF analysis; such modified peptide ions undergo fragmentation at energies lower than those required conventionally for unmodified peptide ions. In this study, we systematically investigated the fragmentation mechanisms of N-terminal sulfonated peptide ions prepared using two different N-terminal sulfonation reagents: 4-sulfophenyl isothiocyanate (SPITC) and 4-chlorosulfophenyl isocyanate (SPC). Collision-induced dissociation (CID) of the SPC-modified peptide ions produced a set of y-series ions that were more evenly distributed relative to those observed for the SPITC-modified peptides; y(n-1) ion peaks were consistently and significantly larger than the signals of the other y-ions. We experimentally investigated the differences between the dissociation energies of the SPITC- and SPC-modified peptide ions by comparing the MS/MS spectra of the complexes formed between the crown ether 18-crown-6 (CE) and the modified peptides. Upon CID, the complexes formed between 18-crown-6 ether and the protonated amino groups of C-terminal lysine residues underwent either peptide backbone fragmentation or complex dissociation. Although the crown ether complexes of the unmodified ([M + CE + 2H]2+) and SPC-modified ([M* + CE + 2H]2+) peptides underwent predominantly noncovalent complex dissociation upon CID, the low-energy dissociations of the crown ether complexes of the SPITC-modified peptides ([M' + CE + 2H]2+) unexpectedly resulted in peptide backbone fragmentations, along with a degree of complex dissociation. We performed quantum mechanical calculations to address the energetics of fragmentations observed for the modified peptides.

Benzenesulfonates↗
PubMed2003

Charge derivatization by 4-sulfophenyl isothiocyanate enhances peptide sequencing by post-source decay matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

High-sensitivity, rapid identification of proteins in proteomic studies normally uses a combination of one- or two-dimensional electrophoresis together with mass spectrometry. The simplicity and sensitivity of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) have increased its application in recent years. The most common method of 'peptide fingerprinting' often may not provide robust identification. Normally additional sequence information by post-source decay (PSD) MALDI-TOFMS provides additional constraints for database searches to achieve highly confident results. Here we describe a derivatization procedure to facilitate the acquisition of such sequence information. Peptide digests from a skin-expressed protein were modified with 4-sulfophenyl isothiocyanate. The resulting peptides carry a fixed negative charge at the N-terminal end and the resulting PSD spectrum is dominated by C-terminal y-type ions. The sequence information in most cases can be obtained manually or with simple programming tools. Methods of optimizing the procedure and increasing the sensitivity are discussed.

Amino Acid Sequence↗
PubMed1985

Analysis of 3-(2-(ethylamino)propyl)-1,2,3,4-tetrahydro-5H(1)benzopyrano (3,4-c)pyridin-5-one in plasma by liquid chromatographic column switching after derivatizing the secondary amine with fluorescein-6-isothiocyanate.

A high-performance liquid chromatographic (HPLC) assay has been developed to quantify the bronchodilator 3-(2-ethylamino)propyl)-1,2,3,4-tetrahydro-5H(1)benzopyrano(3,4-c)pyridi n-5-one (CI-923) (1) in human plasma. The drug and internal standard (2) were extracted from plasma (pH 10.5) with ether, and the secondary amines were derivatized with fluorescein-6-isothiocyanate (F6ITC) (3). The derivatives were isolated from the mixture by on-line HPLC column switching and were quantified with fluorometric detection (Ex: 484 nm; Em: 518 nm). Linearity was observed over the range 0.5-50.0 ng/mL of 1, and the recovery of drug from plasma was greater than 86%. The precision of the method was 3.7-5.2% RSD based on the analysis of seeded control pools containing 0.8, 20.0 and 40.0 ng/mL of 1. The accuracy of the method was +/- 3.3% relative error for the same three pools.

Bronchodilator Agents↗
PubMed1994

Mechanism of the enhancement effect of n-octyl-beta-D-thioglucoside on the transdermal penetration of fluorescein isothiocyanate-labeled dextrans and the molecular weight dependence of water-soluble penetrants through stripped skin.

To clarify the mechanism of the enhancing effect of n-octyl-beta-D-thioglucoside (OTG), which acts as a potent enhancer for skin penetration of peptides and water-soluble penetrants, the in vitro penetration of macromolecules [fluorescein isothiocyanate-labeled dextrans (FTIC-dextrans)] was evaluated with hairless rat skin and stripped skin. The FITC-dextrans (MW, 4400, 9600, and 69,000 Da, referred to as FD-4, FD-10, and FD-70, respectively) penetrated more easily in the presence of OTG (1.5%), with high fluxes equivalent to those through stripped skin. This result indicated that the enhancement effect of OTG on the penetration of macromolecules through the stratum corneum was extensive, and the barrier function of the corneum was nearly eliminated by the OTG treatment. OTG significantly solubilized the stratum corneum proteins and ceramides during the initial time stage. Scanning electron microscopic observations demonstrated that OTG treatment dramatically changed the cell membrane (i.e., exfoliation of cell membranes and dissociation of adherent cornified cells), suggesting a significant disturbance of the cohesive laminae and barrier functions. The extent of dissociation of cell membranes increased with treatment time, without significant changes in the cell junctions. These results clarify that the enhancement mechanism of OTG was different from that of laurocapram and other lipophilic enhancers. The permeability of polar solutes with differing molecular sizes (MW, 180-69,000 Da) through stripped skin was size dependent (r = 0.997, p < 0.001). However, the viable epidermis and dermis restricted the penetration of macromolecules, such as FD-70.

Animals↗
PubMed2006

Analysis of kanamycin A in human plasma and in oral dosage form by derivatization with 1-naphthyl isothiocyanate and high-performance liquid chromatography.

A simple and sensitive HPLC method has been developed for trace determination of kanamycin A by derivatization. Plasma proteins are precipitated by acetonitrile and chemical derivatization is performed on the supernatant containing kanamycin A with 1-naphthyl isothiocyanate in pyridine at 70 degrees C. After the derivatization reaction, a methylamine/acetonitrile solution was added to the reaction mixture to eliminate the excess of derivatizing agent and shorten the analysis time. The resulting derivative was separated using a Lichrocart Purospher STAR RP-18e column and water/methanol (33:67, v/v) as a mobile phase (detection at 230 nm). Optimization conditions for the derivatization of kanamycin A were investigated by HPLC. The linear range for the quantitation of kanamycin A in spiked plasma was over 1.2-40 microg/mL; the detection limit (signal to noise ratio = 3; injection volume, 10 microL) was about 0.3 microg/mL. The relative standard deviation was less than 2.9% for intra-day assay (n = 6) and inter-day assay (n = 6) and relative recoveries were found to be greater than 98%. Preliminary application of the method for monitoring kanamycin A in humans upon intramuscular injection of the injection product demonstrated the usefulness of the assay for clinical studies. The proposed method can also be used to analyze the compound in pharmaceutical formulations.

Administration, Oral↗
PubMed2006

Characterization of amino acids in silk sericin protein from Gonometa rufobrunnae by MEKC with phenyl isothiocyanate derivatization.

An MEKC method was developed for the separation and characterization of phenyl-isothiocyanate (PITC)-labeled amino acids derived from Gonometa rufobrunnae silkworm after microdialysis sample cleanup. The influence of the buffer and SDS concentration on the resolution of the amino acids was investigated. A buffer system consisting of 25 mM phosphate, 10 mM borate buffer at pH 9.00, and 70 mM SDS showed the best results, with 13 PITC-amino acid derivatives being resolved out of 15 possible amino acids that were under study. Microdialysis sampling demonstrated its efficiency as a sample cleanup technique. Sericin protein from G. rufobrunnae was found to be characterized by at least 11 positively identified amino acids. These included His, Tyr, Ser, Ala, Phe, Lys, Gly, Arg, Cys, Glu, and Asp. Leu/Met and Val/Thr were coeluting pairs and hence could not be positively confirmed.

Amino Acids↗
PubMed2005

Role of mitogen-activated protein kinases in phenethyl isothiocyanate-induced apoptosis in human prostate cancer cells.

The present study was undertaken to examine the role of mitogen-activated protein kinases (MAPKs) in apoptosis induction by phenethyl isothiocyanate (PEITC), a cruciferous vegetable-derived cancer chemopreventive agent, with DU145 and LNCaP human prostate cancer cells as a model. The MAPK family of serine/threonine kinases, including extracellular signal-regulated kinase1/2 (ERK1/2), c-jun N-terminal kinase1/2/3 (JNK1/2/3), and p38 MAPK play an important role in cell proliferation and apoptosis in response to different stimuli. Exposure of DU145 and LNCaP cells to growth suppressive concentrations of PEITC resulted in activation of ERK1/2 and JNKs, but not p38 MAPK, in both cell lines. In DU145 cells, the apoptosis induction by PEITC was statistically significantly attenuated by pharmacological inhibition of JNKs with SP600125. Adenovirus-mediated overexpression of Flag-tagged JNK binding domain (JBD) of JNK-interacting protein-1 (JIP-1), an inhibitor of JNK, also inhibited PEITC-induced apoptosis in DU145 cells. On the other hand, inhibition of ERK1/2 activation with MEK1 inhibitor PD98059 failed to offer protection against PEITC-induced apoptosis in DU145 cells. In LNCaP cells, the PEITC-induced cell death was not affected by either pretreatment with PD98059 or SP600125 or overexpression of JBD of JIP-1. These results indicate that involvement of MAPKs in apoptosis induction by PEITC in human prostate cancer cells is cell line-specific.

Apoptosis↗
PubMed2004

De novo sequencing of tryptic peptides sulfonated by 4-sulfophenyl isothiocyanate for unambiguous protein identification using post-source decay matrix-assisted laser desorption/ionization mass spectrometry.

A simple method of solid-phase derivatization and sequencing of tryptic peptides has been developed for rapid and unambiguous identification of spots on two-dimensional gels using post-source decay (PSD) matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The proteolytic digests of proteins are chemically modified by 4-sulfophenyl isothiocyanate. The derivatization reaction introduces a negative sulfonic acid group at the N-terminus of a peptide, which can increase the efficiency of PSD fragmentation and enable the selective detection of only a single series of fragment ions (y-ions). This chemically assisted method avoids the limitation of high background normally observed in MALDI-PSD spectra, and makes the spectra easier to interpret and facilitates de novo sequencing of internal fragment. The modification reaction is conducted in C(18) microZipTips to decrease the background and to enhance the signal/noise. Derivatization procedures were optimized for MALDI-PSD to increase the structural information and to obtain a complete peptide sequence even in critical cases. The MALDI-PSD mass spectra of two model peptides and their sulfonated derivatives are compared. For some proteins unambiguous identification could be achieved by MALDI-PSD sequencing of derivatized peptides obtained from in-gel digests of phosphorylase B and proteins of hepatic satellite cells (HSC).

Amino Acid Sequence↗
PubMed2005

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of 4-sulfophenyl isothiocyanate-derivatized peptides on AnchorChip sample supports using the sodium-tolerant matrix 2,4,6-trihydroxyacetophenone and diammonium citrate.

The reagent 4-sulfophenyl isothiocyanate (SPITC) is an effective, stable, and inexpensive alternative to commercially available reagents used in the N-terminal sulfonation of peptides for enhanced postsource decay (PSD) in matrix-assisted laser desorption/ionization time-of-flight mass spectrometric (MALDI-TOFMS) analyses. However, suppression of ionization of sulfonated peptides due to sample and matrix contaminants such as sodium can be a problem when using prestructured MALDI target sample supports, such as the Bruker Daltonics AnchorChip. We show that use of the salt-tolerant matrix 2,4,6-trihydroxyacetophenone containing diammonium citrate (THAP/DAC) as an alternative to alpha-cyanohydroxycinnamic acid (HCCA) reduces the need for extensive washing of ZipTip-bound peptides or additional on-target sample clean-up steps. Use of the THAP/DAC matrix results in selective ionization of sulfonated peptides with greater peptide coverage, as well as detection of higher mass derivatized peptides, than was observed for HCCA or THAP alone. The THAP/DAC matrix is quite tolerant of sodium contamination, with SPITC-peptides detectable in preparations containing up to 50 mM NaCl. In addition, THAP/DAC matrix was found to promote efficient PSD fragmentation of sulfonated peptides. We demonstrated the utility of using the THAP/DAC MALDI matrix for peptide sequencing with DNA polymerase beta tryptic peptide mixture, as well as tryptic peptides derived from Xiphophorus maculatus brain extract proteins previously separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE).

Acetophenones↗
PubMed2006

Alkylation of opioid receptors by 5'-naltrindole-isothiocyanate injected into the nucleus accumbens of rats: receptor selectivity and anatomical diffusion.

Subtypes of the delta opioid receptor (Oprd1) have been suggested based on pharmacology studies. However, these subtypes have not been confirmed biochemically using either receptor binding assays or molecular cloning. Naltrindole-5'-isothiocyanate (5'-NTII) is an irreversible opioid antagonist that appears to selectively inhibit the actions of a subset of delta opioid agonists in vivo, referred to as putative delta-2 agonists. The biochemical and anatomical selectivity of wash-resistant inhibition of binding of [(3)H]DAMGO (Oprm1), [(3)H]DPDPE (Oprd1, putative subtype 1 agonist), or [(3)H]deltorphin II (Oprd1, putative subytpe 2 agonist) in coronal sections was assessed using quantitative in vitro autoradiography following injection of 5'-NTII into the nucleus accumbens in rats. 5'-NTII decreased [(3)H]deltorphin II to a greater extent than the binding of the other two radioligands following administration of 0.05-2.5 nmol. The effects of 5'-NTII were largely confined to the nucleus accumbens; however, some loss in the ventral caudate was also noted. In contrast, administration of the nonselective opioid receptor alkylating antagonist beta-chlornaltexamine (beta-CNA) over a similar range of doses was found to be nonselective for either delta radioligand, and produced greater inhibition of Oprm1 relative to Oprd1 binding, consistent with the nonselective pharmacological activity of this antagonist. Although 5'-NTII inhibited [(3)H]deltorphin II binding to a greater extent, the binding of the other two radioligands was decreased over a similar range of doses. Absolute conclusions regarding the involvement of delta-2 opioid receptors in pharmacological or physiological effects based on studies with 5'-NTII should therefore be tempered, and for site-directed studies it would be best to employ doses of 0.5 nmol or lower.

Alkylation↗
PubMed2001

Differential effects of naturally occurring isothiocyanates on the activities of cytochrome P450 2E1 and the mutant P450 2E1 T303A.

The effects of benzyl (BITC) and phenethyl isothiocyanate (PEITC) on the activity of a P450 2E1 mutant where the conserved threonine at position 303 was replaced with an alanine residue (P450 2E1 T303A) were examined. PEITC inactivated the mutant enzyme with a K(I) of 1.6 microM. PEITC also inactivated the wild-type P450 2E1 as efficiently with a K(I) of 2.7 microM. The inactivation was entirely dependent on NADPH and followed pseudo-first-order kinetics. Previously we reported the mechanism-based inactivation of wild-type P450 2E1 by BITC with a K(I) of 13 microM. In contrast to the wild-type enzyme, the P450 2E1 T303A mutant was not inactivated by BITC but it was inhibited in a competitive manner with a K(i) of 3 microM. The binding constants determined by spectral binding studies were similar for both enzymes. The binding of BITC produced characteristic Type I spectral changes in the wild-type and mutant enzyme. A radiolabeled BITC metabolite bound to P450 2E1 and to P450 2E1 T303A when both enzymes were incubated with [(14)C]BITC and NADPH. Whole protein electrospray ion trap mass spectrometry indicated that a mass consistent with one molecule of benzylisocyanate and oxygen was adducted to the wild-type enzyme. The mass adducted to the T303A mutant was consistent with the addition of one hydroxylated BITC or of one benzylisocyanate moiety and one sulfur molecule. Analysis of the metabolites of BITC indicated that each enzyme produced similar metabolites but that the mutant enzyme generated significantly higher amounts of benzaldehyde and benzoic acid when compared to the wild-type enzyme.

Animals↗
PubMed1993

Chromatographic analysis of lysosomal degradation of unlabeled native proteins in vitro by fluorescein isothiocyanate labeling.

Fluorescein isothiocyanate (FITC) has high affinity to both Toyopearl HW-40 and Sephadex G-25 gel. FITC-labeled amino acids showed no affinity for Sephadex G-25 whereas FITC-labeled proteins had no affinity. They were eluted in the order FITC-labeled proteins, FITC-labeled amino acids, and free FITC from a small combined column of Sephadex G-25/Toyopearl HW-40, which was prepared by layering a small volume of Toyopearl HW-40 gel on top of a larger volume of Sephadex G-25 gel. These findings were applied to analyzing the degradation of various unlabeled native proteins including L-lactate dehydrogenase (LDH) and rat serum albumin by total lysosomal enzymes in vitro. After degradation, proteins and amino acids released from a substrate protein were labeled with FITC and eluted through the small combined column. FITC-labeled amino acids were easily separated from FITC-labeled proteins and free FITC, and their production increased with degradation time and was markedly suppressed by the proteinase inhibitor leupeptin. The degradation of native LDH was also accompanied by inactivation and the disappearance of the 35-kDa subunit. This procedure is a simple and useful method for studying the proteolytic degradation of various unlabeled proteins by total lysosomal enzymes.

Amino Acids↗
PubMed1995

Synthesis of the protein-sequencing reagent 4-(3-pyridinylmethylaminocarboxypropyl) phenyl isothiocyanate and characterization of 4-(3-pyridinylmethylaminocarboxypropyl) phenylthiohydantoins.

We report the synthesis and structural characterization of the novel Edman-type protein-sequencing reagent 4-(3-pyridinylmethylaminocarboxypropyl) phenyl isothiocyanate. A panel of thiohydantoins prepared from this reagent were found stable during liquid chromatography-electrospray mass spectrometry and were detectable at the low femtomole sensitivity level. Furthermore, the signal detected for these compounds in the mass spectrometer was linear from the low femtomole to the low picomole range. The derivatives showed uv absorbance spectra comparable to their phenylthiohydantoin counterparts. The extinction coefficient for the 4-(3-pyridinylmethylaminocarboxypropyl) phenyl thiohydantoin tyrosine was determined by adsorptive sequence analysis of a synthetic pentapeptide featuring an N-terminal 125I-labeled tyrosine. The sequence data suggest that the reagent will be useful for extended sequence analysis of proteins and peptides using commercially available gas-liquid-phase sequencers.

Amino Acid Sequence↗
PubMed1999

Detection of DBD-carbamoyl amino acids in amino acid sequence and D/L configuration determination of peptides with fluorogenic Edman reagent 7-[(N,N-dimethylamino)sulfonyl]-2,1,3-benzoxadiazol-4-yl isothiocyanate.

A method for amino acid sequence and D/L configuration identification of peptides by using fluorogenic Edman reagent 7-[(N, N-dimethylamino)sulfonyl]-2,1,3-benzoxadiazol-4-yl isothiocyanate (DBD-NCS) has been developed. This method was based on the Edman degradation principle with some modifications. A peptide or protein was coupled with DBD-NCS under basic conditions and then cyclized/cleaved to produce DBD-thiazolinone (TZ) derivative by BF3, a Lewis acid, which could significantly suppress the amino acid racemization. The liberated DBD-TZ amino acid was hydrolyzed to DBD-thiocarbamoyl (TC) amino acid under a weakly acidic condition and then oxidized by NaNO2/H+ to DBD-carbamoyl (CA) amino acid which was a stable and had a strong fluorescence intensity. The individual DBD-CA amino acids were separated on a reversed-phase high-performance liquid chromatography (RP-HPLC) for amino acid sequencing and their enantiomers were resolved on a chiral stationary-phase HPLC for identifying their D/L configurations. Combination of the two HPLC systems, the amino acid sequence and D/L configuration of peptides could be determined. This method will be useful for searching D-amino-acid-containing peptides in animals.

Amino Acid Sequence↗