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Biomedical subjects

K K Han

Publications and source records attributed to K K Han.

At least 55 records · Page 3Linked to original sources
PubMed1984

Special problems encountered during the cyanogen bromide cleavage of lobster arginine kinase.

During structural analysis of Lobster muscle arginine-kinase, we have isolated a CNBr resulting peptide with a blocked N-terminal residue. This peptide was sequenced after unblocking by mild acid treatment (1 N HCl at 100 degrees C for 10 min). The blocked form is not due to the formation of pyroglutamic acid nor is it due to the formation of diketopiperazine. We have applied the experimental conditions used for CNBr cleavage of lobster arginine-kinase to a synthetic peptide the structure of which is similar to the above CNBr peptide. We bring evidence that during CNBr cleavage partial formylation occurs with a possible cyclization of a 7 membered ring of Gly--Asp...

Amino Acid Sequence↗
PubMed1983

Enzymatic cleavage of pyroglutamyl-histidyl-dopamine, a TRH-related pseudo-peptide by porcine serum and brain hoimogenate.

The Pseudo-peptide (pGlu-His-Dopamine) was subjected to enzymatic degradation by porcine serum and brain homogenate. The digests were quantitatively analyzed by HPLC to provide evidence for liberation of pyroglutamic acid and dopamine in serum and of pyroglutamic acid in brain. The yield of liberation of pGlu is about 3% in serum digests and about 0.70% in brain digests after 3 minutes incubation. The time course of the yield of liberation of both pGlu and dopamine in serum digests is determined. The "stability in vitro" toward enzymes of serum and brain homogenate of a new type of drug based on the combination of peptidic fragment of TRH-(Thyrotropin-Releasing Hormone:pGlu-His-Pro-NH2) with a non peptide moiety (dopamine) is considered and discussed.

Animals↗
PubMed1981

Primary structure of lobster-muscle arginine kinase. Amino and carboxyl-terminal structure of the enzyme and complete alignment of the cyanogen-bromide peptides.

The acetylation state of the blocked NH2-terminal end of arginine kinase was characterized by the occurrence of 1 mol acetyl group/mol protein; a 5-residue segment corresponding to the amino-terminal portion was isolated from a pronase digest of the enzyme and its amino acid sequence determined as N-acetyl Ala-Asx-Ala-Thr. Arginine kinase is terminated at the carboxyl end by the sequence Lys-GluMetOH; this particular 3-residue sequence is repeated three times in the overall structure of the protein and is present in three CNBr fragments. One of these, a peptide of 14 amino acid residues, was identified in the course of this study and its amino acid sequence determined. Its location at the COHO-terminal end of the enzyme was recognized on the basis of investigations carried out with des-MetOH-Glu-arginine kinase, a specific proteolytic derivative. The alignment of the eight CNBr-fragments which constitute the arginine kinase molecule was established according to the sequential and compositional properties of seven unique tryptic methionyl peptides isolated from the whole protein. The alignment was confirmed by using BNPS-skatole fragments of the enzyme as another protein source.

Acetylation↗
PubMed1981

Evidence for the enzymic degradation of TRH-related pseudo-peptides by porcine serum and brain homogenate.

Pseudo-peptides (pGlu-His-amphetamine, pGlu-His-pro-Amphetamine and pGlu-amphetamine) were subjected to enzymatic degradation by porcine serum and brain homogenate. The enzymic digests were (qualitatively) analyzed by the "Finger-prints" technique to provide evidence for the presence of free pyroglutamic acid and also quantitatively by HPLC to provide evidence for the presence and yield of free amphetamine. The stability in vitro toward enzymes of serum and brain homogenate of a new type of drug based on the combination of a peptide moiety (TRH) with a non peptide psycho-tropic moiety (amphetamine) is also considered and discussed.

Amphetamines↗
PubMed1981

[Results of leukocyte migration inhibition test against elastin in joint diseases (author's transl)].

UNLABELLED: The purpose of this work was to report the results of the test TML inhibition of leukocytes' migration, using elastin, by Soborg and Bendixen method, modified with elastin rates of 100 micrograms and 200 micrograms/ml, in joints disease. We verified that the test is generally negative in healthy controls (1 TML positive out of 26 cases); we studied 72 patients, and 38 out of them had a positive test. TML is frequently positive in Horton disease, spondylarthritis, rheumatoid polyarthritis without corticoids, collagen disease; in this cases there is a significant difference of migration between patients and controls group. We also noted a positive TML in infections arthritis and other inflammatory but not in joint's diseases with alteration of elastic tissue (scabs and lung's injury). IN CONCLUSION: TML positive test with elastin, is not a specific test of articular injury neither a proof of its immunologic nature but it contributes in diagnostic for joints diseases.

Adult↗
PubMed1981

Partial characterization of peptide fragment purified by isoelectrofocusing after organo alkaline hydrolysis of bovine ligamentum nuchae elastin.

Highly purified elastin from bovine ligamentum nuchae was submitted to partial alkaline hydrolysis (37 degree C, 72 H, 1 N KOH in 80 p. 100 aqueous ethanol). The non-coacervable fractions were submitted to isoelectrofocusing and five kappa-elastin fractions were obtained. The amino-acid compositions, the N-terminal amino-acids, the molecular weights and the thermolysin digests of each fraction were determined by various techniques. The average MW was about 14,500 (150 - 166 amino-acids). These results suggest that the distribution of cross-linking agents in fibrous elastin may not be uniform. The results also show that in certain cross-linked regions of similar molecular weight and size appearing to be composed of different polypeptides sequences containing different amounts of cross-links.

Animals↗
PubMed1979

[Quantitative determination of the activity of acid peptidases of industrial origin].

Reagent ninhydrine-Cd++, reacts with free alpha and epsilon amino groups of proteins. Horse-heart apomyoglobin was subjected to exhaustive succinylation, rendering the product non reactive to ninhydrine. The succinylglobin was submitted to enzyme digestion at pH 2.0, 4.0, 4.7 and 6.0. The commercially available enzymes contain mainly pepsin-like and chymosin-like enzymes. The enzymatic digests of succinyl-globin contain new free alpha-amino groups reacting with ninhydrin. Enzymatic digestion was performed under various condition (ratio E/S, pH). The results were compared to those obtained with synthetic substrate: PRO-HIS-LEU-SER-PHE(NO2)-NLEU-ALA-LEU-OME. The price of the synthetic substrate used, was more than 100 times the cost of succinyl-globin, thus the use of this substrate is a valuable tool for the quantitative estimation of peptidase activity in commercially available (pepsin, chymosin-like) enzymes.

Apoproteins↗
PubMed1979

Evidence for the resistance of thyrotropin-releasing hormone (TRH) and pseudo-hormone, pyroglutamyl histidyl-amphetamine, to degradation by enzymes of the digestive tract in vitro.

TRH and pseudo-hormone (pyro Glu-His-amphetamine) were submitted to the digestion of chymotrypsin and prolidase and independently to the digestion of enzymes of the digestive track: pepsin (stomach), pancreatins (pancreas) and enzymes extracted from the intestinal mucosa (small intestine). Using thin layer chromatography and high voltage electrophoresis techniques to detect enzymic digestion products, only intact TRH and pseudo-hormone were found, indicating that both entities were, under the conditions used, resistant to in vitro digestion by enzymes of the digestive tract.

Amphetamines↗
PubMed1979

Isolation and characterization of desmosine(s) containing peptide fractions of normal and diseases human aortic elastin.

Normal and diseased human aortic elastins were isolated and highly purified. They were subsequently submitted to elastase and thermolysin digestion followed by partial acid hydrolysis to increase crosslinkage. The peptide fractions containing these highly cross-linked desmosines were extensively purified either by ion exchange chromatography or by gel-filtration. Their amino acid composition was determined. Detailed investigation of the purified peptide fraction from normal human elastin containing desmosines was carried out using different N-terminal and C-terminal procedures, thus permitting the probable covalent structure of the desmosine containing peptide(s) to be proposed. Irrespective of their origin (healthy or pathologic), the elastin samples all revealed the same amino acid composition with a very high alanine content in the cross-linking peptides. This work is submitted as proof that changes in amino acid composition are essentially due to "dilution" and contamination by structural glycoproteins and not to structural changes in amino acid compoistion in the vicinal cross-links positions. We find that not only "clustering" alanine residues but also glycine, proline, valine, leucine and tyrosine residues are located in the immediate vicinity of both desmosine and isodesmosine residues.

Amino Acid Sequence↗
PubMed1978

The amino acid sequence of the alpha chain of badger (Meles meles) haemoglobin.

The complete amino acid sequence of the alpha chain from the badger (Meles meles) haemoglobin was elucidated using conventional methods chiefly performed on tryptic peptides separated by peptide "mapping" and comparison with human alpha chain. Sixteen differences were noted between the alpha chain of badger and man. Phylogenetic aspects and three-dimensional structure requirements are discussed.

Amino Acid Sequence↗
PubMed1977

[Preparation of highly purified microbules and evidence for a novel molecular arrangement at low temperatures].

Microtubules were prepared by in vitro polymerization-depolymerization cycles, 1.0 M NaCl which totally depolymerizes was then added to the preparation. After removal of NaCl new arrangements of tubulin were observed at 4 degrees C: simple and double rings as well as fibrils. At 37 degrees these structures disappeared and tubulin polymerized into microtubules. The highly microtubules contain tubulin, tubulin associated proteins of 300,000 and 330,000 molecular weight, minor proteins of low molecular weight and proteins similar to the Tau factors. This raises a question of the role played by low molecular weight polypeptides. Are they products of proteolysis of rather factors of polymerisation?

Animals↗