Claramma M. Chacko

Unstable galactose-1-phosphate uridyl transferase: A new variant of galactosemia

The presence of an unstable form of galactose-1-phosphate uridyl transferase in apatient with clinical galactosemia is described. Galactose-1-phosphate uridyl transferase activity in the red blood cells was approximately 40 per cent of normal and demonstrated storage instability in heparin and isotonic phosphate buffer. Galactose-1-phosphate uridyl transferase from the mother and maternal grandmother demonstrated storge instability and a slower electrophoretic mobility than normal. These data suggest the presence of an additional allele at the transferase locus, which may result in a new variant of clinical galactosemia, hereby referred to as the Indiana variant.

Uridine diphosphoglucose pyrophosphorylase and uridine diphosphogalactose pyrophosphorylase in human skin fibroblasts derived from normal and galactosemic individuals

UDP-Gal pyrophosphorylase (UTP:α-d-galactose-1-phosphate uridyltransferase, EC 2.7.7.10) and UDP-Glc pyrophosphorylase (UTP:α-d-glucose-1-phosphate uridyltransferase, EC 2.7.7.9) activities have been detected in cultivated human skin fibroblasts and their properties compared. UDP-Glc pyrophosphorylase is more stable at 50 and 56° than UDP-Gal pyrophosphorylase while both enzymes have similar Km values, pH optima and electrophoretic mobility. On the basis of the difference in thermal stability, it has been suggested that UDP-Gal pyrophosphorylase is an enzyme distinct from UDP-Glc pyrophosphorylase. A possible alternate pathway for the metabolism of galactose in the galactosemic individuals is discussed.

A study of galactokinase and glucose 4-epimerase from normal and galactosemic skin fibroblasts

Abstract Galactokinase and epimerase from skin fibroblasts of control and galactosemic individuals were studied with respect to specific activity, pH optimum, K m values and thermal stability. The properties of galactokinase and epimerase were similar in control and galactosemic fibroblasts. These data indicate that the mutation at the transferase locus does not alter either the level or the nature of galactokinase and epimerase from skin fibroblasts of control and galactosemic individuals.

The Chicago variant of clinical galactosemia

SummaryA new variant of clinical galactosemia with two hitherto unidentified alleles on the transferase locus in one family is described. This new clinical variant of transferase has 25% of normal control activity in blood and in skin fibroblasts, and the patient accumulates galactose-1-phosphate in blood on an unrestricted galactose diet. Using starch gel electrophoresis on the hemolysate of the family members, a fast-moving transferase with mobility in between those of the normal control and of the Duarte variant is identified. This new allele is designated as n

Immunohistochemical localization of a low molecular weight, soluble protein from bovine lingual epithelium.

GALT^{C_1 }

Unstable Galactose-1-phosphate Uridyl Transferase: A New Variant of Galactosemia

n (fast-moving Chicago variant). In addition, a second new allele was documented in this family by studying the instability of the transferase enzyme in hemolysates of family members at 50°C for various time intervals. This new allele is designated as n

A Low-Molecular-Weight Soluble Protein from Bovine Lingual Epithelium. II. Purification and Characterization

GALT^{C_2 }