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Biomedical subjects

T Inagami

Publications and source records attributed to T Inagami.

At least 451 records · Page 25Linked to original sources
PubMed1977

Purification of high molecular weight forms of renin from hog kidney.

To elucidate the possible regulatory function of high molecular weight renins in blood pressure control, studies were initiated to purify and characterize the high molecular weight enzyme. To avoid the destructive effect of acidification during affinity chromatographic elution, pepstatin-aminobutyl-agarose gel was used from which renin could be eluted at a neutral pH in 2 M urea. Three additional steps of conventional chromatography after the affinity technique produced two types of high molecular weight renins in electrophoretically homogeneous forms. Big renin with a molecular weight of 61,000 has a specific activity approximately 20% of the fully active small molecular weight renin (mol wt 40,000). Big big renins with molecular weights of 140,000 were discovered and purified in two homogeneous forms with specific activities less than 1% of the fully active renin. The possibility of zymogen-enzyme relationship involving the big big, the big, and the fully small molecular weight renins is discussed.

Angiotensin I↗
PubMed1977

Partial purification of human renin.

An affinity gel for the purification of renin was prepared by coupling pepstatin to aminohexylagarose gel. Partially purified human renin (Haas et al., Arch. Biochem. Biophys., 110, 534-543, 1965) was purified further by affinity chromatography on the pepstatin-aminohexyl-agarose gel, gel filtration on a Sephadex G-75 column, and ion exchange chromatography on a DEAE-cellulose column. Separation from a protease permitted further purification without progressive loss of activity. Three peaks of enzymatically active renin were obtained after the DEAE-cellulose chromatography, with specific activities ranging from 206 to 166 and 85 Goldblatt units/mg protein, respectively. The specific activity of 206 GU units/mg represents a 103,000-fold purification compared to the renin present in the first crude extract.

Chromatography, Affinity↗
PubMed1975

Active site directed inactivators of mouse submaxillary renin.

The following active site directed inactivators for the pressor enzyme renin were synthesized: L-alpha-bromo-isocaproyl(BIC)-Leu-Val-Tyr-Ser-OH, L-BIC-Val-Tyr-Ser-OH, L-BIC-Leu-Val-OCH3, L-BIC-Leu-Val-OH, L-BIC-Val-Tyr-NH2, L-BIC-Val-Tyr-OCH3, L-BIC-Val-Tyr-OH, L-BIC-Leu-OCH3, L-BIC-Val-OCH3, and L-BIC-OCH3. The rate of inactivation of mouse submaxillary gland renin by these reagents was studied under a variety of conditions. L-alpha-Bromoisocaproyl-Val-Tyr-Ser-OH and L-alpha-bromoisocaproyl-Leu-Val-Tyr-Ser-OH and L-alpha-bromoisocaproyl-Leu-Val-Tyr-Ser-OH were the most efficient inactivators followed by L-alpha-bromoisocaproyl-Val-Tyr-NH2. The rates of inactivation by the first two peptides were strongly dependent on pH, being most efficient at low pH, least efficient at pH near 5.6, and becoming efficient again at neutral pH. The rate of the inactivation by L-alpha-bromoisocaproyl-Val-Tyr-NH2, in which the C-terminal carboxyl group is blocked, was only slightly dependent on pH. Complete inactivation was achieved by these three reagents. The inactivation was accompanied by incorporation of a stoichiometric quantity of the radiolabeled reagents. Based on these findings it was concluded that the inactivators reacted with a carboxyl group(s) in the active site of the renin molecule to form an esteric linkage. These data also suggest that a carcoxyl group(s) may constitute part of the catalytically essential functional groups in renin action. D-alpha-Bromoisocaproyl derivatives of the various peptides mentioned above were also prepared. These compounds were much less active than the L isomers indicating that the inactivation by the L-alpha-bromoisocaproyl peptides was a specific reaction.

Journal Article↗
PubMed1975

The N, O-diacetylmuramidase of Chalaropsis species. V. The complete amino acid sequence.

The complete amino acid sequence of lysozyme Ch has been established by a combination of automated and manual Edman degradation and carboxypeptidase digestion.(see article)There is a single disulfide bond in the center of the molecule. The enzyme has 211 residues with a calculated molecular weight of 22,415. Lysozyme Ch has an amino acid sequence that is totally different from all other lysozymes whose sequences are known.

Acetates↗
PubMed1975

Chemical modification of amino groups and guanidino groups of trypsin. Preparation of stable and soluble derivatives.

1. Isoionic chemical modification of amino groups of trypsin (EC 3.4.21.4) was studied for the purpose of obtaining a well-defined modified trypsin with minimum changes in physicochemical properties and with sufficient stability at neutral pH. Acetamidination with methyl acetimidate hydrochloride proceeded very rapidly at pH9.8 and 5degrees C and all 14 epsilon-amino groups were modified in 2h. The reaction was limited to epsilon-amino groups. The alpha-amino group of N-terminal isoleucine was modified only by repeated reactions in the presence of 5.5 M-guanidine or 8 M-urea. 2. The epsilon-acetamidinated derivative of beta-trypsin retained enzymic activity at values comparable with those of native enzyme tested with alpha-N-benzoyl-L-arginine ethyl ester and alpha-N-benzoyl-L-arginine p-nitroanilide as substrates; it also showed substrate activation comparable with that of native enzyme. The acetamidination of alpha-trypsin resulted in approx. 50% decrease in its esterolytic activity. 3. The epsilon-acetamidinated beta-trypsin was very stable at pH8 and 25degrees C in the absence of Ca2+. The activity of 0.04% (W/V) enzyme solution remained practically unchanged for 10h, and after 24h 90% of the activity was still retained. Possible autolytic cleavage of peptide bonds of acetamidinated enzymes was followed by N-terminal analysis by using automated Edman degradation. Only the Arg(105)-Val(106) bond was found to be cleaved to an appreciable extent. Thus beta-trypsin can be stabilized simply by complete acetamidination of epsilon-amino groups without modifying guanidino groups of arginine residues. Acetamidinated alpha-trypsin was unstable, but its inactivation at a neutral pH could not be attributed to the cleavage of a single specific peptide bond. 4. The acetamidination of the alpha-amino group of the N-terminal isoleucine results in the inactivation of esterolytic activity. However, this enzyme retained the ability to react with p-nitrophenyl p'-guanidinobenzoate. 5. It was concluded that acetamidination of beta-trypsin is a convenient method for preparing a well-defined stable and soluble trypsin derivative without appreciable change in its physical properties.

Acetamides↗
PubMed1975

Further studies on the existence of a sensitizing factor to pressor agents in hypertension.

Further studies are reported on the existence of a sensitizing factor in plasma of hypertensive subjects, which increases the vascular sensitivity to pressor agents when injected iv into nephrectomized rats. Plasma samples from normotensive subjects, patients with malignant hypertension, normotensive dogs, and dogs with experimental renovascular hypertension were fractionated on Bio-Gel P-10 columns after cold acetone precipitation, and on DEAE-cellulose columns eluted with sodium chloride and pH gradients. The effect of the various fractions on the vascular sensitivity to angiotensin was tested utilizing nephrectomized rats. The sensitizing activity was found only in fractions obtained from plasma of hypertensive patients and dogs and it was concentrated primarily in three fractions. Th results suggest that the sensitizing factor is negatively charged at neutral pH and it could be a polypeptide or a small protein.

Angiotensin II↗