The use of 6-(N-acetyl-L-phenylalanyl)-aminoluciferin as a novel substrate for alpha-chymotrypsin has been demonstrated. The kinetic parameters determined are KM = 0.38 mmol/L, kcat = 6.5 s-1 and kcat/kM = 17,100 (L/mol s). The test principle of the coupled assay is the release of aminoluciferin by enzymatic cleavage of 6-(N-acetyl-L-phenylalanyl)-aminoluciferin. Aminoluciferin is oxidized, with light emission, by firefly luciferase (Photinus pyralis) and can be quantified in a luminometric assay. The detection limit for chymotrypsin was found to be 0.3 ng per assay. 6-(N-acetyl-L-phenylalanyl)-aminoluciferin has been synthesized as an example for a new class of highly sensitive substrates. By modification of the peptide residue these new substrates may be suitable for ultrasensitive detection of different proteinases.

Animals↗

PubMedDate not supplied

Neurochemical effects of the synthetic ACTH4-9-analog Hoe 427 (Ebiratide) in rat brain.

The ACTH4-9-analog Hoe 427 systemically injected in a dose range from 0.01-10 micrograms/kg caused a fall in acetylcholine (ACh) content in different brain areas of the rat. This effect occurred 0.5 hour after a single administration and lasted up to 24 hours. The decrease in ACh content induced by Hoe 427 was more pronounced when the animals were pretreated with dexamethasone (over 7 days 1 mg/kg SC, daily). Coadministration of the choline uptake inhibitor hemicholinium-3 (HC-3) and Hoe 427 potentiated the decrease in ACh content induced by HC-3. In the same dose range Hoe 427 acutely evoked an increase of the activity of the enzyme choline acetyltransferase as well as an elevation of brain cyclic GMP content. These data indicate that Hoe 427 enhances ACh metabolism in rat brain after systemic administration.

Acetylcholine↗

PubMedDate not supplied

Learning and memory processes of an ACTH4-9 analog (ebiratide; Hoe 427) in mice and rats.

These experiments investigated the effects of the new ACTH4-9 analog ebiratide (Hoe 427) [H-Met(O2)-Glu-His-Phe-D-Lys-Phe-NH-(CH2)8-NH2 X 3 CH3COOH] on memory processes in mice and rats in five training tasks. With all five training and testing procedures (inhibitory avoidance test with ECS- or scopolamine-induced amnesia, up-hill avoidance, one-way shuttle box avoidance and eight-arm radial maze) ebiratide was most effective in a dose range of 1-10 micrograms/kg SC.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

[Blood pressure difference between upper arm and thigh, and aortic stiffness in healthy subjects and in patients after coarcectomy].

BACKGROUND: The blood pressure difference between the right arm and the legs is often used as an estimate of a possible gradient across a coarctation or recoarctation aortae. We wanted to test the reliability of this hypotheses while estimating the local stiffness of the aortae ascendens and abdominalis. PATIENTS: We examined 50 healthy children and adolescents as well as 50 patients of a similar age after repair of an coarctation aortae. There was no relevant recoarctation on echocardiography or magnet resonance tomography. METHODS: We measured in all patients the blood pressure by oscillometry three times on the right upper arm and thigh. At the same time we measured the systolic and diastolic diameter of the aorta before the branching of the truncus brachiocephalicus and the branching of the truncus coeliacus. The local stiffness was calculated, using the stiffness index b, from the aortic diameter and the corresponding blood pressure. RESULTS: The systolic blood pressure difference showed in healthy subjects and patients after coarctation a wide range (about 60 mm Hg). The diastolic and mean blood pressure showed a slightly smaller range. There was no significant difference in this respect between the two groups. The stiffness index beta was elevated after coarcectomy in the aorta ascendens compared to healthy subjects. The local stiffness of the abdominal aortae were similar in both groups and showed a similar increase with advancing age. DISCUSSION: The blood pressure difference between the upper arm and thigh showed a wide range. Therefore is the blood pressure difference an unreliable tool to estimate the severity of a re-coarctation. The local stiffness of the aorta ascendens was elevated after coarctation and implied at least a partial loss of the Windkessel. The local stiffness in the aorta abdominalis was normal after coarctation repair.

Adolescent↗

PubMedDate not supplied

[Insulin analogs with B-chains shortened at the N-terminal end. Selective Edman degradation of the insulin B chain (author's transl)].

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Amino Acid Sequence↗