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Biomedical subjects

L Gráf

Publications and source records attributed to L Gráf.

At least 91 records · Page 5Linked to original sources
PubMed1976

Hirudin.

Explore the source record for details and available documents.

Amino Acid Sequence↗
PubMed1976

Fragmentation of porcine beta-lipotropic hormone with plasmin.

Porcine beta-lipotropic hormone was digested by plasmin and the fragments released were isolated and identified. Based on the structure and the yield of the plasmin fragments and also on the time-course of the digestion, the relative sensitivity of the theoretically susceptible bonds towards the action of plasmin was estimated. The Lys79-Asn80 bond was the most susceptible to plasmin, the Arg51-Trp52 and Arg60-Tyr61 bonds were split to a lesser extent than the Lys79-Asn80 bond, but much faster than the Lys46-Met47, Lys69-Ser70 and Lys84-Asn85 bonds of the beta-lipotropic homone structure. Further lysyl and arginyl bonds of the molecule were not attacked under our experimental conditions.

Amino Acid Sequence↗
PubMed1976

Isolation and evolution of the gastrointestinal hormones.

The history of the discovery of gastrointestinal hormones and the modern methods of their isolation are discussed in the first chapter. The origin of structural relationships of gastrointestinal hormones and the possible ways of evolution are analyzed in the second chapter. The methods used for isolation and identification of secretin and cholecystokinin are dealt with in detail; the isolation of vasoactive intestinal peptide, gastrin, "gastric inhibitory peptide" and enteroglucagon is discussed but briefly in the first chapter. The second chapter is of speculative character. It deals with the structural resemblances between gastrin-type (gastrin, cholecystokinin-pancreozyzimin, caerulein) and secretin-type (secretin, vasoactive intestinal peptide, glucagon, "gastric inhibitory peptide") hormones. The resemblances are explained by different evolutionary mechanisms.

Amino Acid Sequence↗
PubMed1975

Selective reduction and alkylation of the COOH-terminal disulfide bridge in bovine growth hormone.

Conditions leading to the cleavage of both disulfide bridges in human growth hormone caused the reduction of only one disulfide bond in bovine growth hormone. Partially reduced and alkylated derivatives of bovine growth hormone were prepared and characterized. It was shown that the reduction and alkylation modified the COOH-terminal disulfide bond, however, this modification does not result in the dissociation of the dimeric form of bovine growth hormone or cause a significant loss of growth-promoting activity.

Alkylation↗
PubMed1974

Human pituitary growth hormone: isolation and properties of two biologically active fragments from plasmin digests.

Two biologically active fragments have been isolated from plasmic digests of human pituitary growth hormone. It was shown that these two fragments were derived from the cleavage of the Arg-Thr (positions 134-135) and the Lys-Gln (positions 140-141) bonds of the hormone: one has 134 amino acids and the other 51 amino acids, respectively. The two fragments were active in the rat tibia and pigeon crop-sac tests, as well as in complement fixation experiments.

Amino Acid Sequence↗