A case of weak blood group B expression (Bm) associated with abnormal blood group galactosyltransferase

Blood ◽  
1982 ◽  
Vol 59 (2) ◽  
pp. 323-327
Author(s):  
A Yoshida ◽  
K Yamato ◽  
V Dave ◽  
H Yamaguchi ◽  
Y Okubo
Keyword(s):  
Blood Group ◽  
Cell Membranes ◽  
Transferase Activity ◽  
Red Cell ◽  
Direct Mutation ◽  
Group A ◽  
Michaelis Constants ◽  
Normal Enzyme ◽  
Red Cell Membranes ◽  
Group B

The mechanisms of unusually weak A and B blood group expressions have not been well understood. Since the human blood group A and B substances are produced by the action of blood group GalNAc transferase and Gal transferase, respectively, the mechanism may be elucidated by examining the properties of the blood group transferases and membranes of the subjects with the abnormality. We examined a case associated with very weak B activity in red blood cells, an absence of the B agglutinin in serum, and an existence of the H and B substances in saliva, i.e., a case commonly classified as Bm. More than 85% of H sites remained unglycosylated in the subject's red cell membranes. The blood group Gal transferase activity in the subject's plasma and red cell membranes was about 50% of that of normal. The pH-activity profile and the Michaelis constants for UDP-Gal and 2'-fucosyllactose of the subject's enzyme were distinctively different from that of normal enzyme. These findings led us to conclude that the weak B activity in the present Bm case was due to a direct mutation in B gene resulting in formation of variant B enzyme with low affinity to UDP-Gal and insufficient galactosylation of H sites in the subject.

scholarly journals A case of weak blood group B expression (Bm) associated with abnormal blood group galactosyltransferase

Blood ◽  
1982 ◽  
Vol 59 (2) ◽  
pp. 323-327 ◽  
Author(s):  
A Yoshida ◽  
K Yamato ◽  
V Dave ◽  
H Yamaguchi ◽  
Y Okubo
Keyword(s):  
Blood Group ◽  
Cell Membranes ◽  
Transferase Activity ◽  
Red Cell ◽  
Direct Mutation ◽  
Group A ◽  
Michaelis Constants ◽  
Normal Enzyme ◽  
Red Cell Membranes ◽  
Group B

Abstract The mechanisms of unusually weak A and B blood group expressions have not been well understood. Since the human blood group A and B substances are produced by the action of blood group GalNAc transferase and Gal transferase, respectively, the mechanism may be elucidated by examining the properties of the blood group transferases and membranes of the subjects with the abnormality. We examined a case associated with very weak B activity in red blood cells, an absence of the B agglutinin in serum, and an existence of the H and B substances in saliva, i.e., a case commonly classified as Bm. More than 85% of H sites remained unglycosylated in the subject's red cell membranes. The blood group Gal transferase activity in the subject's plasma and red cell membranes was about 50% of that of normal. The pH-activity profile and the Michaelis constants for UDP-Gal and 2'-fucosyllactose of the subject's enzyme were distinctively different from that of normal enzyme. These findings led us to conclude that the weak B activity in the present Bm case was due to a direct mutation in B gene resulting in formation of variant B enzyme with low affinity to UDP-Gal and insufficient galactosylation of H sites in the subject.

scholarly journals Membrane abnormality in red blood cells with weak type B expression

Blood ◽  
1980 ◽  
Vol 56 (5) ◽  
pp. 881-885 ◽  
Author(s):  
A Yoshida ◽  
H Fujii ◽  
V Dave ◽  
MJ Cozant ◽  
PA Morel
Keyword(s):  
Blood Group ◽  
Kinetic Properties ◽  
Red Cell ◽  
Nucleotide Sugar ◽  
Red Cell Membrane ◽  
Direct Mutation ◽  
Group A ◽  
Blood Group Substances ◽  
Membrane Components ◽  
Secondary Consequence

Abstract The mechanisms of unusually weak blood group (A and B) expressions are not yet well understood. We examined properties of blood group galactosyltransferase (B-enzyme) and characteristics of red cell membrane components obtained from family members with A2Bm character. B- enzyme activity of the A1Bm plasma is in normal range, and kinetic properties (i.e., Km for UDP-Gal, Km for 2′-fucosyllactose, and pH optima) of B-enzyme from the A1Bm subjects are identical to that of normal B-enzyme. When A1Bm red cell were incubated with UDP-Gal and B- enzyme, the cells became strongly agglutinable with anti-B. When A1Bm membranes were incubated with B-enzyme or A-enzyme (i.e., blood group N- acetylgalactosaminyltransferase) and the appropriately labeled nucleotide sugar (UDP-Gal3H for B-enzyme and UDP-GalNAc3H for A- enzyme), significant incorporation of the sugar was observed. The amounts of the sugar incorporated into A1Bm membranes were about 40%- 50% of that incorporated into O membranes at saturation, indicating that about one-half of H-sites remained unglycosylated in A1Bm red cells. Examination of radioactive components by isoelectric focussing revealed that the labeled components of A1Bm membranes were distinctively different from that of O membranes. Therefore, one can conclude that the weak B expression is not due to direct mutation of ABO locus, but due to a secondary consequence of genetic abnormality of a membrane component (or components) associated with blood group substances.

scholarly journals Membrane abnormality in red blood cells with weak type B expression

Blood ◽  
1980 ◽  
Vol 56 (5) ◽  
pp. 881-885
Author(s):  
A Yoshida ◽  
H Fujii ◽  
V Dave ◽  
MJ Cozant ◽  
PA Morel
Keyword(s):  
Blood Group ◽  
Kinetic Properties ◽  
Red Cell ◽  
Nucleotide Sugar ◽  
Red Cell Membrane ◽  
Direct Mutation ◽  
Group A ◽  
Blood Group Substances ◽  
Membrane Components ◽  
Secondary Consequence

The mechanisms of unusually weak blood group (A and B) expressions are not yet well understood. We examined properties of blood group galactosyltransferase (B-enzyme) and characteristics of red cell membrane components obtained from family members with A2Bm character. B- enzyme activity of the A1Bm plasma is in normal range, and kinetic properties (i.e., Km for UDP-Gal, Km for 2′-fucosyllactose, and pH optima) of B-enzyme from the A1Bm subjects are identical to that of normal B-enzyme. When A1Bm red cell were incubated with UDP-Gal and B- enzyme, the cells became strongly agglutinable with anti-B. When A1Bm membranes were incubated with B-enzyme or A-enzyme (i.e., blood group N- acetylgalactosaminyltransferase) and the appropriately labeled nucleotide sugar (UDP-Gal3H for B-enzyme and UDP-GalNAc3H for A- enzyme), significant incorporation of the sugar was observed. The amounts of the sugar incorporated into A1Bm membranes were about 40%- 50% of that incorporated into O membranes at saturation, indicating that about one-half of H-sites remained unglycosylated in A1Bm red cells. Examination of radioactive components by isoelectric focussing revealed that the labeled components of A1Bm membranes were distinctively different from that of O membranes. Therefore, one can conclude that the weak B expression is not due to direct mutation of ABO locus, but due to a secondary consequence of genetic abnormality of a membrane component (or components) associated with blood group substances.

scholarly journals ABO groups can play a role in susceptibility and severity of COVID-19

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
S. Samra ◽  
M. Habeb ◽  
R. Nafae
Keyword(s):  
Blood Group ◽  
Abo Blood Group ◽  
Infection Group ◽  
Mechanically Ventilated ◽  
Blood Group A ◽  
Group A ◽  
Study Population ◽  
Group B ◽  
The Relationship ◽  
Seriously Ill

Abstract Background A few people infected by the coronavirus become seriously ill, while others show little to no signs of the symptoms, or are asymptomatic. Recent researches are pointing to the fact that the ABO blood group might play an important role in a person’s susceptibility and severity of COVID-19 infection. Aim of the study: try to understand the relationship between ABO groups and COVID-19 (susceptibility and severity). Results A total of (507) patients were included in this study. The study population was divided based on the ABO blood group into types A+, A−, B+, AB, O+, and O−. Blood group A was associated with high susceptibility of infection: group A, 381 (75.1%); and less common in group O, 97 (19.2%), group B, 18 (3.5%), and group AB, 11 (2.2%). The severity of COVID-19 infection was common in non-blood group O where (20 (7.1%), 4 (26.7%), 2 (11%), and 1 (9%) in type A+, A−, B+, and AB, respectively), while in type O 3.1%. And mechanically ventilated patients were 22 (5.9%), 2 (13.4%), 2 (11.1%), and 1 (1%). Mortality was high in blood groups A and B, 16 (4.37%) and 1 (5.5%), respectively, while in blood group O, it was 1%. Conclusion The incidence, severity, and mortality of COVID-19 were common in non-blood group O. While blood group O was protected against COVID-19.

BRIEF REPORT: Freeze-Cleaving of Red Cell Membranes in Paroxysmal Nocturnal Hemoglobinuria

Blood ◽  
1967 ◽  
Vol 30 (6) ◽  
pp. 785-791 ◽  
Author(s):  
RONALD S. WEINSTEIN ◽  
ROGER A. WILLIAMS
Keyword(s):  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Cell Membranes ◽  
Red Cells ◽  
Red Cell ◽  
Electron Microscopic ◽  
Structural Differences ◽  
Microscopic Studies ◽  
Red Cell Membranes

Abstract Electron microscopic studies on dried isolated red cell ghosts have been reported to show lesions associated with cell membranes in paroxysmal nocturnal hemoglobinuria (PNH). In this study, carbon-platinum replicas of membranes of freeze-cleaved, partially hydrated PNH red cells and isolated PNH cell ghosts failed to confirm the existence of these abnormalities. This suggests that the previously described lesions are the products of drying artifacts, although they may reflect hidden structural differences between PNH and normal red cell membranes.

scholarly journals Temperature effects on sodium pump phosphoenzyme distribution in human red blood cells.

1985 ◽  
Vol 85 (1) ◽  
pp. 123-136 ◽  
Author(s):  
J H Kaplan ◽  
L J Kenney
Keyword(s):  
Atpase Activity ◽  
Cell Membranes ◽  
Conformational Transition ◽  
Fold Increase ◽  
Inhibitory Effect ◽  
Red Cell ◽  
Na Pump ◽  
Na Ions ◽  
Red Cell Membranes ◽  
Increasing Temperature

Phosphorylation of red cell membranes at ambient temperatures with micromolar [32P]ATP in the presence of Na ions produced phosphoenzyme that was dephosphorylated rapidly upon the addition of ADP or K ions. However, as first observed by Blostein (1968, J. Biol. Chem., 243:1957), the phosphoenzyme formed at 0 degrees C under otherwise identical conditions was insensitive to the addition of K ions but was dephosphorylated rapidly by ADP. This suggested that the conformational transition from ADP-sensitive, K-insensitive Na pump phosphoenzyme (E1 approximately P) to K-sensitive, ADP-insensitive phosphoenzyme (E2P) is blocked at 0 degrees C. Since the ATP:ADP exchange reaction is a partial reaction of the overall enzyme cycle dependent upon the steady state level of E1 approximately P that is regulated by [Na], we examined the effects of temperature on the curve relating [Na] to ouabain-sensitive ATP:ADP exchange. The characteristic triphasic curve seen at higher temperatures when [Na] was between 0.5 and 100 mM was not obtained at 0 degrees C. Simple saturation was observed instead with a K0.5 for Na of approximately 1 mM. The effect of increasing temperature on the ATP:ADP exchange at fixed (150 mM) Na was compared with the effect of increasing temperature on (Na + K)-ATPase activity of the same membrane preparation. It was observed that (a) at 0 degrees C, there was significant ouabain-sensitive ATP:ADP exchange activity, (b) at 0 degrees C, ouabain-sensitive (Na + K)-ATPase activity was virtually absent, and (c) in the temperature range 5-37 degrees C, there was an approximately 300-fold increase in (Na + K)-ATPase activity with only a 9-fold increase in the ATP:ADP exchange. These observations are in keeping with the suggestion that the E1 approximately P----E2P transition of the Na pump in human red cell membranes is blocked at 0 degrees C. Previous work has shown that the inhibitory effect of Na ions and the low-affinity stimulation by Na of the rate of ATP:ADP exchange occur at the extracellular surface of the Na pump. The absence of both of these effects at 0 degrees C, where E1 approximately P is maximal, supports the idea that external Na acts through sites on the E2P form of the phosphoenzyme.

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