Possibility of lifetime measurement in a flowing medium with phase fluorometry

The possibility of lifetime measurement in a flowing medium with phase fluorometry is investigated theoretically. A 3-D time dependent partial differential equation of the number density of atoms (or molecules) in the upper level of the fluorescence transition is solved analytically, taking flow, diffusion, optical excitation, decay, Doppler shift, and thickness of the excitation light sheet into account. An analytical expression of the intensity of the fluorescence signal in the flowing medium is deduced. Conditions are given, in which the principle of lifetime measurement with phase fluorometry in the static sample cell can be used in a flowing medium.

The amino acid sequence and properties of an edema-inducing Lys-49 phospholipase A2 homolog from the venom of Trimeresurus mucrosquamatus

Three phospholipase A2 enzymes or homologs were purified from the venom of Trimeresurus mucrosquamatus (Taiwan habu). The most abundant one was found to be a phospholipase homolog without enzyme activity, and its complete amino acid sequence was determined using oligopeptide fragments derived from digestion by endopeptidases Glu-C, Asp-N, Lys-C and alpha-chymotrypsin, and by means of gas-phase sequencing. The sequence revealed that the protein belonged to the Lys-49 family of snake venom phospholipase A2. This protein's function was characterized as edema-inducing. The Lys-49 protein has the potential to bind membrane phospholipid and Ca2+ (Kd = 1.6 x 10(-4) M) as shown by ultraviolet difference spectra; however, the catalytic site appeared to be inactive and the edematous response was independent of the protein's hydrolytic activity. Mast cells and platelets were shown to be subject to activation by the Lys-49 protein.

Triflavin, an antiplatelet Arg-Gly-Asp-containing peptide, is a specific antagonist of platelet membrane glycoprotein IIb-IIIa complex

Triflavin, an antiplatelet peptide containing Arg-Gly-Asp, purified from Trimeresurus flavoviridis venom, inhibits aggregation of human platelets stimulated by a variety of agonists. It blocks aggregation through interference with fibrinogen binding to its specific receptor on the platelet surface membrane in a competitive manner, but it has no apparent effect on intracellular events, such as thromboxane B2 formation, phosphoinositides breakdown and intracellular Ca2+ mobilization of thrombin-activated platelets. In this study, we determined the complete sequence of triflavin, which is composed of a single polypeptide chain of 70 amino acids. Its sequence is rich in cysteine and contains Arg-Gly-Asp at residues 49-51 in the carboxy-terminal domain. Triflavin shows about 68% identity of amino acid sequence with trigramin, which is a specific antagonist of the fibrinogen receptor associated with glycoprotein IIb/IIIa complex. [125I]Triflavin binds to unstimulated and ADP-stimulated platelets in a saturable manner and its Kd values are estimated to be 76 and 74 nM, respectively; the corresponding numbers of binding sites are 31,029 and 34,863 per platelet, respectively. [125I]Triflavin binding is blocked by Gly-Arg-Gly-Asp-Ser in a competitive manner. EDTA, the Arg-Gly-Asp-containing peptides (including naturally occurring polypeptides, trigramin and rhodostomin), and monoclonal antibody, 7E3, raised against GP IIb/IIIa complex, inhibit [125I]triflavin binding to unstimulated and ADP-stimulated human platelets. In conclusion, triflavin specifically binds to fibrinogen receptor associated with GP IIb/IIIa complex and its binding site is located at or near GP IIb/IIIa complex, overlapping with those of 7E3 and another Arg-Gly-Asp-containing polypeptide, rhodostomin.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification, characterization, and molecular cloning of gonadotropin subunits of silver carp (Hypophthalmichthys molitrix)

The alpha and beta subunit of silver carp gonadotropin (scGTH-alpha and scGTH-beta) were isolated by high-performance liquid chromatography. Heterogeneity of N-terminal amino acid sequence was observed in scGTH-alpha but not in scGTH-beta. For determining the complete primary structures of scGTH-alpha and scGTH-beta, their cDNAs were cloned. Combining the data of N- and C-terminal sequences determined from proteins and the amino acid sequences deduced from cDNAs, we infer that scGTH-alpha consists of 95 and/or 93 residues and scGTH-beta consists of 115 residues. Both scGTH-alpha and scGTH-beta are glycoprotein. Their carbohydrate content is about 20 g per 100 g protein. The molecular weights of scGTH-alpha and scGTH-beta were calculated to be 12,700 and 15,700 Da, respectively. The amino acid sequences of scGTH-alpha and scGTH-beta are very similar to those of the corresponding subunit of carp GTH, different in only 2 and 4 residues, respectively. In addition, a high extent of homology (70%) was also observed between the alpha subunits of fish and mammalian GTHs. In the case of beta subunit, homology among various species of fish (75 to 98%) is much higher than that between fish and mammal (40%). These data suggest that the alpha subunit is conserved while the beta subunit is diversified during the molecular evolution of vertebrate GTH.

Fast atomic line filter/field ionization detector

An experimental demonstration of a fast atomic line filter/field ionization detector (FALF/FID) is presented. The FALF/FID detects incoming signal photons by resonant absorption in an atomic vapor cell containing a strong electric field. Excited atoms are electric-field ionized after further excitation to a Stark-shifted Rydberg level by a pump laser tuned to a resonance in the ionization spectrum, providing an observed enhancement in the ionization rate of ten times over the continuum ionization threshold. Preliminary measurements of time response (<10 nsec) and quantum efficiency (>25%) indicate that with optimization the FALF/FID will provide high quantum efficiency, fast time response, and narrow-linewidth detection.

Revised amino acid sequences of the three major phospholipases A2 from Bungarus fasciatus (banded krait) venom

The structures of three cardiotoxin-like proteins obtained from the venom of Bungarus fasciatus (banded krait) were elucidated previously (Lu and Lo, 1980, 1981). Since their molecular sizes are similar to that of phospholipase A2 and since they show weak phospholipase A2 activities (Chang et al., 1983), a further study of their primary structures was carried out. Fractions Va, Vb-2 and VI, corresponding to the former V-2, V-3 and VI were determined to be typical phospholipases A2. Among 118 amino acid residues, they all have in common a Pro29 between Gly28 and Gly30, the latter two residues being implicated in Ca2+ binding together with Tyr26 and Asp47.

Pike eel (Muraenesox cinereus) gonadotropin. Amino acid sequences of both alpha and beta subunits

The amino acid sequences of pike eel gonadotropin alpha and beta subunits have been determined by standard sequencing analytical methods. The alpha subunit is composed of 93 amino acid residues while the beta subunit comprises 113 amino acid residues. All the invariant half-cystine residues are in the same positions as those found in other gonadotropins. It is noteworthy that the first, putative glycosylation site (Asn56) found in the alpha subunit of other gonadotropins was replaced by Asp56 in the alpha subunit of pike eel gonadotropin. Similarity analyses indicate that both subunits are structurally more similar to other known fish gonadotropin subunits than to those of the mammalian gonadotropins.

Amino acid sequence of a neutral phospholipase A2 (III) in the venom of Bungarus fasciatus

Two phospholipases were found in the venom of Bungarus fasciatus, one in fraction III, the other in fraction X of the chromatographic separation. A neutral PLA2(III) purified from fraction III was subjected to amino acid sequencing by means of an automated sequenator applied to the intact RCM-PLA2 (III) and the individual peptides obtained from HPLC separation of the three types of enzymatic peptides. PLA(III) was shown to consist of 118 amino acid residues with 14 half-cystines. It is 65% homologous to the basic PLA2 obtained from fraction X.

Unusual amino acid sequence of fasciatoxin, a weak reversibly acting neurotoxin in the venom of the banded krait, Bungarus fasciatus

A weak reversibly acting neurotoxin, fasciatoxin, was found in the venom of Bungarus fasciatus. The sequencing was completed by manual and automated Edman analyses of the reduced and carboxymethylated protein and of the peptides obtained from enzyme digestions. It is composed of 63 amino acid residues with four disulphide bonds and a unique sequence at the C-terminal end. According to the criteria set by Ryden, Gabel & Eaker [(1973) Int. J. Pept. Protein Res. 5, 261-273], fasciatoxin lacks all of the five functionally invariant residues of neurotoxins. The hydropathy index indicates that fasciatoxin is devoid of a strong hydrophilicity domain for binding to the receptor site. Structural comparison with some typical neurotoxins also reveals the uniqueness of fasciatoxin in that the extent of similarity is only about 30%.

Double-blind crossover controlled study on antiepilepsirine

Antiepilepsirine (AES) is one of the derivatives of a Chinese folk prescription. It is a new antiepileptic drug (AED) synthesized in cooperation by Chinese medical and pharmaceutical workers. Pharmacological experiments on animal models prove that its antiepileptic action is marked, but there has been little evaluation of its clinical effects. We used the double-blind placebo-controlled crossover study which is generally acceptable as a proper method for new drug study. This study covered 58 epileptic children treated with classical AEDs and observed 6.5 months. Every patient took AES and placebo for 3 months each by random crossover on the basis of add-on therapy. The blood levels of AES and other antiepileptic drugs were determined regularly. The results show that there are no significant differences in clinical effects between AES and placebo in pediatric epilepsies as a whole, but AES is effective in tonic-clonic seizures (P less than 0.05), the most common type of seizure in the series. There are no significant differences in AED blood levels between the AES effective and ineffective groups. AES has no effect on the blood levels of other AEDs. AES is very safe, children given large doses (10 mg/kg/day) demonstrate no serious side-effects. It is suggested that there is potential improvement in patient psychological and cognitive status. This article also discusses the evaluation of new drugs for clinical effects, subject sampling, the criteria for efficacy evaluation and relationship between animal information and human outcome. The AES chemical structure is different from other well-known AEDs, this is a unique advantage.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino acid sequence of a short chain neurotoxin from the venom of banded krait (Bungarus fasciatus)

The amino acid sequence of a short chain neurotoxin obtained from Bungarus fasciatus venom consists of 64 amino acid residues: Arg-Ile-Cys-Leu-Asn-Gln-Gln-Gln-Ser- Thr-Pro-Glu-Asp-Gln-Pro-Thr-Asn-Gly-Gln-Cys-Tyr-Ile-Lys-Thr-Asp-Cys-Gln- Asn-Lys - Thr-Trp-Asn-Thr-His-Arg-Gly-Ser-Arg-Thr-Asp-Arg-Gly-Cys-Gly-Cys-Pro-Lys- Val-Lys - Pro-Gly-Ile-Asn-Leu-Arg-Cys-Cys-Lys-Thr-Asp-Lys-Cys-Asn-Glu. The above result was obtained primarily from the amino acid analyses and sequencing of tryptic peptides accompanied with the necessary analyses and sequencing of the chymotryptic and lysyl endopeptidic peptides for alignment.

The complete amino-acid sequence of a basic phospholipase A2 in the venom of Bungarus fasciatus

A basic phospholipase A2 (PLA2) was isolated and purified from the venom of Bungarus fasciatus. Four kinds of enzymes, lysyl endopeptidase, endoproteinase Asp-N, endoproteinase Glu-C and trypsin, were employed to elucidate the complete primary structure by means of gas-phase sequencing. The amino-acid sequence reveals 118 amino-acid residues containing seven pairs of half-cystine. It has 78% and 61% structural identities with PLA2 from Bungarus multicinctus and Naja melanoleuca DE-II, respectively.

The prevalence and morphology of cataract in patients on allopurinol treatment

We have shown that an unusual morphological thinning of the anterior clear zone of the lens is found in patients with gout on long term Allopurinol therapy. The significance of this is discussed.

The heparin binding site of human antithrombin III. Selective chemical modification at Lys114, Lys125, and Lys287 impairs its heparin cofactor activity

Heparin binds to human antithrombin III and accelerates its inhibitory activity in the blood coagulation system. Previous reports (Rosenberg, R. D., and Damus, P. S. (1973) J. Biol. Chem. 248, 6490-6505; Pecon, J. M., and Blackburn, M. N. (1984) J. Biol. Chem. 259, 935-938) have shown that selective chemical modification of a limited number of lysine residues in antithrombin III causes drastic loss of its heparin cofactor activity. We have performed chemical modification of antithrombin III with trinitrobenzene sulfonic acid in order to determine the location of these lysine residues. When antithrombin III was treated with 100 M excess of trinitrobenzene sulfonic acid for 10 min, about 3.2 mol of amino group per mol of antithrombin III were modified. The heparin cofactor activity dropped to about 25%, whereas the progressive inhibitory activity (in the absence of heparin) remained essentially intact (about 95%). The modified amino groups were identified to be Lys114 (75%), Lys125 (94%), and Lys287 (96%). These results were obtained by comparing and analyzing the cyanogen bromide fragments derived from native antithrombin III and the 10-min modified antithrombin III. When antithrombin III was pretreated with heparin, followed by trinitrobenzene sulfonic acid modification, the extent of modification at Lys114 and Lys125 decreased from 75% and 94% to 20% and 40%, respectively, whereas the modification at Lys287 remained nearly quantitative (greater than 95%). Based on these results, we conclude that Lys114 and Lys125 are essential for the heparin cofactor activity of human antithrombin III.

Probing the heparin-binding domain of human antithrombin III with V8 protease

From structural analysis on genetically abnormal and chemically modified human antithrombin III [Koide, T., Odani, S., Takahashi, K., Ono, T. and Sakuragawa, N. (1984) Proc. Natl Acad. Sci. USA 81, 289-293; Chang, J.-Y. and Tran, T. H., (1986) J. Biol. Chem. 261, 1174-1176; Blackburn, M. N., Smith, R. L., Carson, J. and Sibley, C. C. (1984) J. Biol. Chem. 259, 939-941], the heparin-binding site of antithrombin III has been suggested to be in the region of Pro-41, Arg-47 and Trp-49. In this study the heparin-binding site was probed by preferential cleavage of V8 protease on heparin-treated and non-treated native antithrombin III. The study has been based on the presumption that the heparin-binding site of antithrombin III is situated at exposed surface domain and may be preferentially attacked during limited proteolytic digestion. Partially digested antithrombin III samples were monitored by quantitative amino-terminal analysis and amino acid sequencing to identify the preferential cleavage sites. 1-h-digested antithrombin III was separated on HPLC and peptide fragments were isolated and characterized both qualitatively and quantitatively. The results reveal that Glu-Gly (residues 34-35), Glu-Ala (residues 42-43) and Glu-Leu (residues 50-51) are three preferential cleavage sites for V8 protease and their cleavage, especially the Glu-Ala and the Glu-Leu sites, was drastically inhibited when antithrombin III was preincubated with heparin. Both high-affinity and low-affinity antithrombin-III-binding heparins were shown to inhibit the V8 protease digestion of native antithrombin III, but the high-affinity sample exhibited a higher inhibition activity than the low-affinity heparin. These findings (a) imply that the segment containing residues 34-51 is among the most exposed region of native antithrombin III and (b) support the previous conclusions that this region may play a pivotal role in the heparin binding.

Complete amino acid sequences of two protease inhibitors in the venom of Bungarus fasciatus

Two analogous protease inhibitors, VIIIb and IX in the venom of Bungarus fasciatus were reduced and carboxymethylated. Tryptic peptides were separated by cellulose thin-layer peptide mapping technique, and amino acid sequences were analyzed by DABITC/PITC double coupling method. Alignment of all tryptic peptides was established by analyses of chymotryptic peptides and further confirmed by Staphylococcus aureus V8 protease digestion. IX consisted of 65 amino acid residues. VIIIb consisted of 62 residues, identical to the N-terminal 62-amino acid sequence of IX.

Bathymetry CuBr laser

The design and performance of a short-pulse high-repetition-rate CuBr laser suitable for bathymetry is described. The pulse width and peak power were 4.5 nsec and 30 kW, respectively, corresponding to 140 microJ/pulse. These conditions occurred at a repetition rate of 16 kHz and an overall efficiency of 0.14% within a compact long-lived sealed-off discharge.

Preparation and chemical characterization of the three chains of the major hemoglobin of the sea snake, Pelamis platurus

One of the 2 main hemoglobins of the sea snake Pelamis platurus, (the Yellow-bellied sea snake) comprising about 70% of the total hemoglobin, was separated by DEAE-Sephadex column chromatography. From results of gel filtration and iron content determination, both intact sea snake hemoglobin, and the isolated major hemoglobin, were concluded to be composed of 4 subunits with a molecular weight of 66,000-67,000 daltons. Separation of the chains of globin of the major hemoglobin by CM 52 column chromatography gave 3 peaks, named, chains a, b, and c. The approximate molecular weights of chains a, b, and c were deduced by SDS gel electrophoresis to be 14,000, 16,000, and 20,000 daltons, respectively. The peptide maps and amino acid compositions of the three chains were distinctly different. N-Terminal and C-terminal amino acid sequence studies reveal that chains a, b, and c represented the alpha-chain, beta-chain, and beta'-chain differing from the normal beta-chain in having a C-terminal sequence of -Arg-Leu-His-Tyr. From the peak areas of the 3 chains obtained by CM 52 column chromatography, and the peak sizes of the 3 bands separated by SDS gel electrophoresis, it was concluded that the sea snake hemoglobin is composed of a hybrid tetramer, alpha2betabeta'.

Double heterozygosity for hemoglobin Camden (beta 131 Gln yields Glu) and hemoglobin S in an American negro

A hemoglobin variant with the slightly fast mobility associated with K hemoglobins was found, together with hemoglobin S, in an apparently healthy 3-year-old Negro girl from Washington, D.C. Her father had the same variant, along with hemoglobin A, and her mother had hemoglobins A plus S. Respective proportions of hemoglobins K and S in the propositus were 66-34. The K variant now has been found to have the structural change Gln yields Glu at position beta-131 (beta-H9); therefore it apparently is identical to hemoglobin Camden reported in trait form in a Negro subject by YATES, BELLINGHAM and HUEHNS (Nature 243: 467-468, 1973).