Decreased activities of liver microsomal drug-metabolizing enzymes in the rats bearing walker carcinosarcoma

Riassunto Ratti portatori di carcinosarcoma di Walker, presentano una notevole diminuzione di attività di quel gruppo di enzimi microsomici epatici da cui dipende il metabolismo di una numerosa serie di farmaci. I nostri rilievi sono stati fatti prendendo in considerazione il metabolismo dell'esobarbital, della stricnina e del meprobamato.     

Collagenase-like peptidase activity in serum from patients with rheumatoid arthritis

Summary The activities of collagenase-like peptidase, estimated by using (succinyl-Gly-Pro-Leu-Gly-Pro-Leu-Gly-Pro)-4-methyl-coumaryl-7-amide as substrate, and of dipeptidyl-aminopeptidase IV were decreased in the sera from patients with rheumatoid arthritis. Both enzymes bring about the degradation of peptides derived from collagen. A significant positive correlation was observed between the activities of the two serum peptidases.     

Structural basis for recognition of acidic-cluster dileucine sequence by GGA1

GGAs (Golgi-localizing, gamma-adaptin ear homology domain, ARF-interacting proteins) are critical for the transport of soluble proteins from the trans-Golgi network (TGN) to endosomes/lysosomes by means of interactions with TGN-sorting receptors, ADP-ribosylation factor (ARF), and clathrin. The amino-terminal VHS domains of GGAs form complexes with the cytoplasmic domains of sorting receptors by recognizing acidic-cluster dileucine (ACLL) sequences. Here we report the X-ray structure of the GGA1 VHS domain alone, and in complex with the carboxy-terminal peptide of cation-independent mannose 6-phosphate receptor containing an ACLL sequence. The VHS domain forms a super helix with eight alpha-helices, similar to the VHS domains of TOM1 and Hrs. Unidirectional movements of helices alpha6 and alpha8, and some of their side chains, create a set of electrostatic and hydrophobic interactions for correct recognition of the ACLL peptide. This recognition mechanism provides the basis for regulation of protein transport from the TGN to endosomes/lysosomes, which is shared by sortilin and low-density lipoprotein receptor-related protein.     

Bradykinin-potentiating peptides from the venom ofAgkistrodon halys blomhqffii

Zusammenfassung Aus dem Gift vonAgkistrodon halys blomhoffii konnten durch Säulenchromatographie an Sephadex G-100, G-25 und CM-Sephadex C-50 fünf Peptidkomponenten isoliert werden, welche die kontrahierende Wirkung von Bradykinin auf den isolierten Meerschweinchendarm signifikant erhöhen.

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Part of this paper was presented at the 41st Annual Meeting of the Japanese Biochemical Society, Tokyo (1968).     

Phenobarbital markedly increases liver weight in walker carcinosarcoma bearing rats

Riassunto Gli autori hanno dimostrato che nei ratti portatori di tumore di Walker (carcinosarcoma 256), un trattamento eseguito 48 h prima con phenobarbital produce un aumento del rapporto peso fegato/peso corporeo pari al 26%, mentre esso è soltanto del 6% dei ratti normali. Tale fatto si accompagna ad aumento di contenuto totale di proteine, di RNA e di DNA.     

Structure in the early afterglow light curve of the gamma-ray burst of 29 March 2003

Gamma-ray bursts (GRBs) are energetic explosions that for 0.01-100 s are the brightest gamma-ray sources in the sky. Observations of the early evolution of afterglows are expected to provide clues about the nature of the bursts, but their rapid fading has hampered such studies; some recent rapid localizations of bursts have improved the situation. Here we report an early detection of the very bright afterglow of the burst of 29 March 2003 (GRB030329). Our data show that, even early in the afterglow phase, the light curve shows unexpectedly complicated structures superimposed on the fading background.     

Inhibition of pentobarbital and meprobamate metabolism by some ‘inducers’ of drug-metabolizing enzymes

Riassunto Gli autori hanno dimostrato che alcuni farmaci (p.e. la clorciclizina, la glutetimide, il fenaglicodolo, il fenobarbital, la clorpromazina, il cloretone ed altri), che posseggono una tardiva attività «inducente» di stimolo su enzimi microsomici epatici, attivi nel metabolismo di svariati farmaci, determinano invece una inibizione degli enzimi stessi quando vengano fatti agire direttamente.