Premium
Molecular mass determination for prostate‐specific antigen and α 1 ‐antichymotrypsin complexed in vitro
Author(s) -
Bedzyk William D.,
Larsen Barbara,
Gutteridge Steve,
Ballas Robert A.
Publication year - 1998
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1111/j.1470-8744.1998.tb00502.x
Subject(s) - molecular mass , chemistry , mass spectrometry , amino acid , prostate specific antigen , residue (chemistry) , mole , hydrolysis , chromatography , population , antigen , biochemistry , prostate , enzyme , biology , medicine , environmental health , cancer , genetics
The results from molecular mass determinations and amino acid analyses for prostate‐specific antigen (PSA), α 1 ‐antichymotrypsin (ACT) and PSA‐ACT complexed in vitro are reported. Molecular masses for two separate PSA‐ACT lots were determined by matrix‐assisted laser desorption ionization mass spectroscopy (MALDI‐MS) coupled to a time‐of‐flight (TOF) detector. Interestingly, both PSA‐ACT lots contained two predominant protein species: 78095± 138 Da (approx. 67% of total protein) and 82519± 104 Da. Because a heterogeneous population was observed and the masses were less than expected on the basis of less sensitive techniques, molecular masses for the individual PSA and ACT components were determined. As expected, PSA possessed a single molecular mass (27755.8 Da). Each ACT raw material lot, however, also contained two predominant species: 55106± 111 and 51414± 32 Da. To assess the amino acid composition, each PSA, ACT and PSA‐ACT lot was subjected to acid hydrolysis for 24, 48 and 72 h followed by amino acid analysis. Experimental results, expressed as mole percentages for each measurable residue and the number of residues per mole of protein, were compared with both the predicted and previously published values and were as expected. These more accurate molecular mass values for ACT and purified PSA‐ACT complex should be considered in preparing and characterizing international standard preparations.