Accumulation of two glycoasparagines in the liver in aspartylglycosaminuria.

Two water-soluble glycoasparagine storage products were isolated from the liver of a patient with inherited deficiency of lysosomal N-aspartyl-beta-glucosaminidase (aspartylglycosaminuria). The compounds were characterized using gas chromatographic-mass spectrometric analyses of intact and specifically degraded derivatives. The storage compounds were identified as 2-acetamido-1-N-(4'-L-aspartyl)-2-deoxy-beta-D-glucopyranosylamine and alpha-D-mannopyranosyl-(1 leads to 6)-beta-D-mannopyranosyl-(1 leads to 4)-2-acetamido-2-deoxy-beta-D-glucopyranosyl-(1 leads to 4)-2-acetamido-1-N-(4'-L-aspartyl)-2-deoxy-beta-D-glucopyranosylamine. Their amounts in the pathological liver were approximately 2.7 mg/g and 0.2 mg/g, wet weight, respectively. These glycoasparagines are structurally related to the inner core region of a number of different glycoproteins.