Effect of differentiation on hydrolysis and association of Leu-enkephalin to K562(S) cells.
Hydrolysis of Leu-enkephalin and association to cells of the peptide-radioactive label have been studied on the K562(S) erythroleukemic cell subline. Data obtained indicate that in the presence of these cells, Leu-enkephalin is hydrolyzed, that the peptide's radioactive label is partially associated to cells, and that these phenomena are related. Hydrolysis and association are inversely modified by the cells' differentiation: hydrolysis is increased and association is decreased in differentiated compared with nondifferentiated cells. Moreover, the ratio of hydrolysis by-products is dissimilar between differentiated and nondifferentiated cells as a result of a significant modification of the soluble enzymes' release. The alterations induced by differentiation on all parameters investigated seem to indicate significant changes in the membrane structures responsible for the mechanisms controlling these phenomena.
Dipartimento di Medicina Sperimentale, Università di Roma Tor Vergata, Rome, Italy.
A
A
Urbani
L
L
Bongiorno
M
M
Marini
F
F
Bolacchi
C
C
Zona
L G
LG
Roda
D000595:Amino Acid Sequence; D002454:Cell Differentiation; D004151:Dipeptides / Q000737:chemistry / Q000378:metabolism; D010450:Endopeptidases / Q000302:isolation & purification / Q000378:metabolism; D004743:Enkephalin, Leucine / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism* / Q000473:pathology; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D014443:Tyrosine / Q000378:metabolism
D004151:Dipeptides; D009842:Oligopeptides; D011480:Protease Inhibitors; C044757:tyrosyl-glycyl-glycine; D014443:Tyrosine; D004743:Enkephalin, Leucine; D010450:Endopeptidases