Biomaterial Database

Abnormal red cell membrane proteolytic activity in severe heterozygous beta-thalassemia. 1982

S K Ballas, and E R Burka, and F M Gill

A 63-year-old man of italian origin with severe heterozygous beta-thalassemia whose clinical condition deteriorated after splenectomy is described. The alpha/beta synthesis ration in the peripheral blood was 3.02 +/- 0.56 and in the bone marrow 1.43. The free alpha-chain pool comprised 73% of the total radioactive alpha-globin in the peripheral blood and 68% in the bone marrow. RBC membranes isolated from erythrocytes incubated in the presence of 14C-leucine were practically devoid of nascent beta-chains with an alpha/beta ratio of 5.12 +/- 1.47, significantly higher than that present in the corresponding hemolysate. RBC membranes from this patient, compared to control membrane preparations, showed increased proteolytic activity directed against tetrameric hemoglobin and beta-hemoglobin chains, with concomitant decreased catabolism of alpha-hemoglobin chains. RBC membranes from individuals with mild beta-thalassemia trait and from transfused patients with homozygous beta-thalassemia degraded alpha-hemoglobin chains more efficiently than those from the patient described. The data suggest that decreased degradation of the alpha-chain by RBC membranes from this patient might lead to progressive accumulation of this polypeptide and expansion of the free alpha-chain pool, which, in turn, may be responsible for the severity of the clinical picture.

UI	MeSH Term	Description	Entries
D007930	Leucine	An essential branched-chain amino acid important for hemoglobin formation.	L-Leucine,Leucine, L-Isomer,L-Isomer Leucine,Leucine, L Isomer
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D010447	Peptide Hydrolases	Hydrolases that specifically cleave the peptide bonds found in PROTEINS and PEPTIDES. Examples of sub-subclasses for this group include EXOPEPTIDASES and ENDOPEPTIDASES.	Peptidase,Peptidases,Peptide Hydrolase,Protease,Proteases,Proteinase,Proteinases,Proteolytic Enzyme,Proteolytic Enzymes,Esteroproteases,Enzyme, Proteolytic,Hydrolase, Peptide
D011480	Protease Inhibitors	Compounds which inhibit or antagonize biosynthesis or actions of proteases (ENDOPEPTIDASES).	Antiprotease,Endopeptidase Inhibitor,Endopeptidase Inhibitors,Peptidase Inhibitor,Peptidase Inhibitors,Peptide Hydrolase Inhibitor,Peptide Hydrolase Inhibitors,Peptide Peptidohydrolase Inhibitor,Peptide Peptidohydrolase Inhibitors,Protease Antagonist,Protease Antagonists,Antiproteases,Protease Inhibitor,Antagonist, Protease,Antagonists, Protease,Hydrolase Inhibitor, Peptide,Hydrolase Inhibitors, Peptide,Inhibitor, Endopeptidase,Inhibitor, Peptidase,Inhibitor, Peptide Hydrolase,Inhibitor, Peptide Peptidohydrolase,Inhibitor, Protease,Inhibitors, Endopeptidase,Inhibitors, Peptidase,Inhibitors, Peptide Hydrolase,Inhibitors, Peptide Peptidohydrolase,Inhibitors, Protease,Peptidohydrolase Inhibitor, Peptide,Peptidohydrolase Inhibitors, Peptide
D001853	Bone Marrow	The soft tissue filling the cavities of bones. Bone marrow exists in two types, yellow and red. Yellow marrow is found in the large cavities of large bones and consists mostly of fat cells and a few primitive blood cells. Red marrow is a hematopoietic tissue and is the site of production of erythrocytes and granular leukocytes. Bone marrow is made up of a framework of connective tissue containing branching fibers with the frame being filled with marrow cells.	Marrow,Red Marrow,Yellow Marrow,Marrow, Bone,Marrow, Red,Marrow, Yellow
D004910	Erythrocyte Membrane	The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.	Erythrocyte Ghost,Red Cell Cytoskeleton,Red Cell Ghost,Erythrocyte Cytoskeleton,Cytoskeleton, Erythrocyte,Cytoskeleton, Red Cell,Erythrocyte Cytoskeletons,Erythrocyte Ghosts,Erythrocyte Membranes,Ghost, Erythrocyte,Ghost, Red Cell,Membrane, Erythrocyte,Red Cell Cytoskeletons,Red Cell Ghosts
D004912	Erythrocytes	Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.	Blood Cells, Red,Blood Corpuscles, Red,Red Blood Cells,Red Blood Corpuscles,Blood Cell, Red,Blood Corpuscle, Red,Erythrocyte,Red Blood Cell,Red Blood Corpuscle
D005260	Female		Females
D005914	Globins	A superfamily of proteins containing the globin fold which is composed of 6-8 alpha helices arranged in a characterstic HEME enclosing structure.	Globin