title: Alpha-l-iduronidase and arylsulfatase B in dried blood spots on filter paper: Biochemical parameters and time stability.
abstract: BACKGROUND
  The goal of this study was to assess the biochemical parameters of the enzymes α-l-iduronidase (IDUA) and arylsulfatase B (ASB), which are deficient in mucopolysaccharidosis (MPS) I and VI, respectively, in dried blood spot (DBS) samples impregnated on filter paper.
  
  
  RESULTS
  The optimal pH, Km, and Vmax of IDUA and ASB in DBS are hereby presented. After these analyses, the reference values for the activities of these enzymes in DBS with cutoff of 3.65nmol/h/mL for IDUA and 6.80nmol/h/mL for ASB were established. The research also showed that the stability (21days) of the IDUA activity is lower than ASB, which maintained its enzymatic activity stable up until 60days of analysis, after impregnating the filter paper with blood.
  
  
  CONCLUSIONS
  Currently, DBS ensures important advantages in handling storage and transportation of samples with respect to neonatal screening programs. This study contributes to characterizing and differentiating the biochemistry of deficient enzymes in MPSs I and VI of DBS samples.
authors.affiliation: Postgraduate Program, Biochemistry Department, Lysosomal Storage Diseases Laboratory, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. Electronic address: anacarolina.breier@gmail.com.
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Breier
authors.affiliation: Postgraduate Program, Biochemistry Department, Lysosomal Storage Diseases Laboratory, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Jaqueline
authors.initials: J
authors.lastname: Cé
authors.affiliation: Postgraduate Program, Biochemistry Department, Lysosomal Storage Diseases Laboratory, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Jamila
authors.initials: J
authors.lastname: Mezzalira
authors.affiliation: Postgraduate Program, Biochemistry Department, Lysosomal Storage Diseases Laboratory, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Vanessa V
authors.initials: VV
authors.lastname: Daitx
authors.affiliation: Postgraduate Program, Biochemistry Department, Lysosomal Storage Diseases Laboratory, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Vitoria C
authors.initials: VC
authors.lastname: Moraes
authors.affiliation: Postgraduate Program, Biochemistry Department, Lysosomal Storage Diseases Laboratory, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Mariana P S
authors.initials: MPS
authors.lastname: Goldim
authors.affiliation: Postgraduate Program, Biochemistry Department, Lysosomal Storage Diseases Laboratory, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Janice C
authors.initials: JC
authors.lastname: Coelho
mesh_terms: D059788:Dried Blood Spot Testing / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D007068:Iduronidase / Q000097:blood*; D008297:Male; D008059:Mucopolysaccharidosis I / Q000097:blood*; D009085:Mucopolysaccharidosis IV / Q000097:blood*; D020051:N-Acetylgalactosamine-4-Sulfatase / Q000097:blood*
chemical_list: D020051:N-Acetylgalactosamine-4-Sulfatase; C581941:ARSB protein, human; C000615655:IDUA protein, human; D007068:Iduronidase
keywords: Alpha-l-iduronidase; Arylsulfatase B; Km; Maximum velocity; Mucopolysaccharidosis; Optimum pH