Metabolic Studies of a Heavy Chain Disease Protein

摘要: The metabolic behavior of a heavy chain disease protein (γ HCD-JM) has been investigated in four patients with normal IgG levels, the patient himself, G-myeloma and myotonic dystrophy. was isolated from urine, labeled 131I administered once to each patients. The γ HCD-JM belongs G3 subclass its catabolic is like that intact proteins same subclass. survival half time 6.6 days fractional rate 39.5% per day similar immunoglobulins. resembles pooled (predominantly composed IgG1 molecules) several other properties. Thirty-nine cent distributed intravascular pool, as compared 44% for IgG. this altered by serum level. Subjects hypercatabolism associated dystrophy or high levels (multiple myeloma) also have shortened HCD (FCR). proteinuric low, Two pool lost proteinuria daily. These findings support concept Fc portion molecule determines IgG. Studies metabolism himself show FCR slightly elevated synthetic (0.42 g/kg/day mean synthesis 0.034 individuals). This indicates accumulation H-chain does not arise defective catabolism but due excessive synthesis.