Specificity in the hydrolysis of N-acyl-L-phenylalanine 4-nitroanilides by chymotrypsin

Summary The affinity of N-acyl-L-phenylalanine 4-nitroanilides for chymotrypsin is enhanced as the hydrophobicity of non-amino acid residues in the P₂-position of the substrates increases, whereas k_cat remains nearly constant. On the other hand, if alanine or leucine is in the P₂-position k_cat increases with decreasing K_M.     

The short-term effects of a single dose of erythropoietin upon reticulocytes in starved rats

Zusammenfassung Nach einer Injektion von Erythropoietin in hungernde Ratten beobachteten wir eine Erhöhung der Reticulocyten. Junge Formen von Reticulocyten erschienen bereits 12 h nach der Behandlung. Dieser Befund deutet vielleicht darauf hin, dass Erythropoietin nicht nur die Stammzellen angreift.

---

---

Supported by Grant No. CY-3071 from the U.S.P.H.S.     

Wiederherstellung des normalen Herzschlages nach elektrisch erzeugtem Kammerflimmern durch Adenosintriphosphorsäure

Summary (1) In the isolated mammalian heart (rabbit, cat, dog) electrically induced ventricular fibrillation is stopped in practically 100% of the cases by adenosin-triphosphoric acid (ATP) in doses of 0.25–20 mg, and the normal rhythm of the heart is permanently restored (as far as the experiment extends).(2) This effect of ATP follows from a primary blocking, which leads to a complete cessation of the activity of the ventricles with diastolic dilatation of the heart.(3) In as much as adenyl acid from yeast and adenosin (in large doses) also stop ventricular fibrillation, the energetic effect of ATP seems to be of no importance in stopping it; it is a specific effect of the adenyl compounds on the bundle ofHis.     

Étude électrophorétique concernant les protéines et les acides nucléiques tissulaires a propos de l'inhibition de la cancérogenèse

Summary Cancerous or leukotic tissue fragments modified by a 24 h subcutaneous implantation in the rabbit, become capable of favouring the inhibition of cancerogenesis.This paper is concerned with the study of proteins and nucleic acids of the so-treated implants.