Structure of human milk bile salt activated lipase

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00216a028· OSTI ID:5674319

Baba, T; Downs, D; Jackson, K W; Tang, J; Wang, Chi-Sun ^[1]

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1. Univ. of Oklahoma Health Science Center, Oklahoma City (USA)

The structure and some functional sites of human milk bile salt activated lipase (BAL) were studied by cDNA cloning and chemical analysis of the enzyme. Eighteen cDNA clones of human BAL were identified from lactating human breast cDNA libraries in {lambda}gt11 and {lambda}gt10 with antibody and synthetic oligonucleotides as probes. The sequence of four clones was sufficient to construct a 3018-bp BAL cDNA structure. This sequence codes for an open reading frame of 742 amino acid residues. There is a putative signal sequence of 20 residues which is followed by the amino-terminal sequence of BAL, and the mature BAL contains 722 amino acid residues. The cDNA sequence also contains a 678-base 5{prime}-untranslated sequence, a 97-base 3{prime}-untranslated region, and a 14-base poly(A) tail. The sequence of a 1.8-kbp insert of clone G10-4A differs from that of the other cDNA in that it contains a deletion of 198 bases (1966-2163) corresponding to 66 amino acid residues. By use of BAL cDAN as probe, it was found that the major molecular species of BAL mRNA in human mammary gland HBL-100 cells had a size of 2.9 kb and two minor species had sizes of 3.8 and 5.1 kb by Northern blot analyses. These chemical studies established that the active site of human milk BAL is located at serine-194, the N-glycosylation site is present at asparagine-187, the O-glycosylation region is in the 16 repeating units near the C-terminus, and the heparin binding domain is in the N-terminal region. The authors have also determined the location of disulfide bridges as Cys64-Cys80 and Cys246-Cys257. The cyanogen bromide cleavage and the partial sequencing of CNBr peptides also confirmed the location of methionines in the polypeptide chain as well as the deduced cDNA sequence of BAL.

• OSTI ID: 5674319
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 30:2; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AGE GROUPS
AMINO ACID SEQUENCE
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BILE
BIOLOGICAL MATERIALS
BODY FLUIDS
CARBOXYLESTERASES
CARBOXYLIC ACIDS
CHILDREN
CYANOGEN
DAYS LIVING RADIOISOTOPES
DIGESTION
DNA
DNA SEQUENCING
ENZYMES
ESTERASES
EVEN-ODD NUCLEI
FEMALES
FOOD
HYDROLASES
HYDROXY ACIDS
INFANTS
ISOTOPES
LIGHT NUCLEI
LIPASES
MAMMALS
MAN
MATERIALS
MILK
MOLECULAR STRUCTURE
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
OLIGONUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PRIMATES
PURIFICATION
RADIOISOTOPES
RECOMBINANT DNA
SERINE
STRUCTURAL CHEMICAL ANALYSIS
SULFUR 35
SULFUR ISOTOPES
VERTEBRATES
WOMEN