Excess alpha chains are lost from beta-thalassemic reticulocytes by proteolysis

Journal Article · Tue Sep 01 00:00:00 EDT 1981 · J. Lab. Clin. Med.; (United States)

OSTI ID:5102953

Testa, U; Hinard, N; Beuzard, Y; Tsapis, A; Galacteros, F; Thomopoulos, P; Rosa, J

During incubation of reticulocytes from patients with beta-thalassemia, after labeling of the hemoglobin with radioactive amino acids, the excess alpha chains are gradually lost from the cells. The aim of this study was to investigate the mechanism of this phenomenon. A system was developed in which reticulocytes from beta-thalassemia patients are labeled with (3H)leucine, washed several times in nonradioactive medium, and then incubated in the same medium containing puromycin added in order to stop further protein synthesis. The results have clearly shown that excess alpha chains are gradually degraded by proteolysis. N-ethylmaleimide or epsilon-aminocaproic acid inhibited the proteolysis of free alpha chains. The addition of either ATP or hemin did not change the rate of alpha chain degradation. The time required to degrade 50% of the pool of free alpha chains was directly dependent on the initial value of this pool. This finding suggests the absence of a significant individual variation in the ability to proteolyse free alpha chains.

• OSTI ID: 5102953
• Journal Information: J. Lab. Clin. Med.; (United States), Vol. 98:3
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PROTEOLYSIS
BIOCHEMICAL REACTION KINETICS
THALASSEMIA
PATHOLOGY
TRITIUM COMPOUNDS
ISOTOPE APPLICATIONS
BIOLOGICAL PATHWAYS
HEMOGLOBIN
LEUCINE
PATIENTS
RETICULOCYTES
AMINO ACIDS
ANEMIAS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DECOMPOSITION
DISEASES
ERYTHROCYTES
GLOBIN
HEMIC DISEASES
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
KINETICS
LABELLED COMPOUNDS
MATERIALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PIGMENTS
PORPHYRINS
PROTEINS
REACTION KINETICS
SYMPTOMS
550901* - Pathology- Tracer Techniques
550201 - Biochemistry- Tracer Techniques
550301 - Cytology- Tracer Techniques