PMID- 1806365
OWN - NLM
STAT- MEDLINE
DCOM- 19920511
LR  - 20190918
IS  - 0013-9432 (Print)
IS  - 0013-9432 (Linking)
VI  - 45
IP  - 1-2
DP  - 1991
TI  - The mechanism of decline of age-dependent enzymes in the red blood cell.
PG  - 47-53
AB  - Buoyant density centrifugation on discontinuous gradients separates red blood 
      cells (RBCs) according to age, as shown by radiolabelling experiments both in 
      vitro and in vivo. Changes observed in these gradients reflect in vivo rates of 
      decline. A progressive metabolic decline may render the RBC incapable of 
      surviving stresses in the circulation. It was hypothesized that changes only take 
      place at the reticulocyte-mature RBC transition. RBC hexokinase (HK) has two 
      isozymes, one predominant in reticulocytes, the other in mature RBCs. We compared 
      its decline in the density gradient, with that of pyrimidine-5'-nucleotidase 
      (P5N), glutamate-oxaloacetate transaminase (GOT) and pyruvate kinase (PK). The 
      decline of HK and P5N was clearly biphasic; for GOT and PK instead there was a 
      single slope. Thus changes taking place at the reticulocyte-RBC transition are 
      clearly identified by a biphasic slope in the gradient. The view of a progressive 
      metabolic decline in vivo for the RBC therefore remains valid.
FAU - Haram, S
AU  - Haram S
AD  - Division of Pediatric Hematology/Oncology, Columbia University, College of 
      Physicians and Surgeons, New York, N.Y.
FAU - Carriero, D
AU  - Carriero D
FAU - Seaman, C
AU  - Seaman C
FAU - Piomelli, S
AU  - Piomelli S
LA  - eng
GR  - DK26793-11/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Switzerland
TA  - Enzyme
JT  - Enzyme
JID - 1262265
RN  - 0 (Isoenzymes)
RN  - EC 2.6.1.1 (Aspartate Aminotransferases)
RN  - EC 2.7.1.1 (Hexokinase)
RN  - EC 2.7.1.40 (Pyruvate Kinase)
RN  - EC 3.1.3.5 (5'-Nucleotidase)
SB  - IM
MH  - 5'-Nucleotidase/metabolism
MH  - Aging/*metabolism
MH  - Aspartate Aminotransferases/metabolism
MH  - Erythrocytes/*enzymology
MH  - Hexokinase/metabolism
MH  - Humans
MH  - *Isoenzymes
MH  - Kinetics
MH  - Pyruvate Kinase/metabolism
MH  - Statistics as Topic
EDAT- 1991/01/01 00:00
MHDA- 1991/01/01 00:01
CRDT- 1991/01/01 00:00
PHST- 1991/01/01 00:00 [pubmed]
PHST- 1991/01/01 00:01 [medline]
PHST- 1991/01/01 00:00 [entrez]
AID - 10.1159/000468864 [doi]
PST - ppublish
SO  - Enzyme. 1991;45(1-2):47-53. doi: 10.1159/000468864.